Life after dinoflagellates

Donya · Oct 24, 2024

It's been an extremely long time since I've posted anything to do with my tanks in this section. I've had two, 20gal nanos for years and years and had many beautiful successes with those tanks. I got bombed with dinoflagellates a few years ago after a move. No idea where they came from; maybe they were always there in small quanities and just went bonkers for some reason. It started as a patch of what I was sure was cyano that I couldn't seem to do anything to and it just kept growing and CUC kept mysteriously disappearing. For those unfamiliar with that pest, calling dinoflagellates catastrophic is not an exaggeration. They are certainly the worst thing I've ever had to deal wtih. Although not true for all species, mine really did look indistinguishable from cyano by day, so I had to get lucky and check the tank at around 3AM one night to realize all this "cyano" I couldn't put a dent in suddenly looked pretty weird (dinos get wiggly at certain times of night - but mine basically waited until the witching hour to do it rather than right after lights off). Many species are toxic for CUC to eat, so I lost all but a couple of hitchhiker-type inverts. It even nearly wiped out my bristleworms. I had read and heard in my many years of reef keeping that combatting the stuff is brutal and can destroy the tank no matter what approach you tank. Folks aren't kidding about that. Dinos are robust to light deprivation so they can outlast corals with blackout treatments, they thrive in low nutrient systems so a skimmer can actually make it worse, and they don't give up easily even if you switch to a high nutrient regime - they will bloom even more at first. Whatever variety I had also looooved a good invasive tank cleaning. About 48h after any attempt I made to vigorously clean the tanks, they got dino-bombed even worse than before the cleaning. By the time I realized what I was really dealing with, many corals had also been melted by it, although some of my more potent soft corals, BTAs, and two fish were fine. I really wondered about getting out of the hobby at that point since I'm more of an invert person than anything else. I also started to get paranoid about my RODI system - was my TDS meter broken? Was some mystery chemical sneaking through in unmeasurable quantities and being my enemy? Nope, I think that's just what it's like when you get a bad batch of dinos, and you either have to nuke them chemically or ecologically and ecologically is hard.

I was never able to identify what species of dinos I had, so I opted to try to fight them naturally and tediously via just a slightly higher level of nutrients. I read/heard of too many short-term success but long-term failure cases using more sophistocated nutrient dosing to try anything else in such a small volume of water. Live rock also seems rather hard to get in small quantities these days so I didn't want to nuke my rock with a chemical treatment and risk killing my corals and creating what might have to be fish-only systems for a long time. My tanks have always maintained such a high population of pods due to the 1-fish-per-tank stocking that I hardly had to feed the fish; everything had become low nutrient...so I just fed the fish more a bit more frequently and decided to see where that took me, since that which had survived the dinos so far seemed to be hanging in there without too much issue. It took about 2 years and running two UV sterilizers per tank 24/7 at two different flow rates to be rid of the stuff without resorting to invert-toxic and potentially coral-toxic chemical treatments.

Of course, once the dinos were beaten back, something else annoying would bloom. To not deal with follow-up mini blooms of dinos, I had to basically let whatever wanted grow in its place do so and not disturb it too much as the ecosystem iteratively tried to right itself and different species of algaes slowly overtook one another. So, I have been staring at two embarassing, absolute scuzzy algae messes of tanks for the past couple years, each with zero CUC, some mucky-looking soft corals and anemones, and just a single fish per tank that is a strangely critical pin of the nutrient system. Robust pods survived, so I have a rich ecosystem of teeny-tiny creatures, just not anything that can eat larger algae - so naturally hair algae finally won the algae battle. My canister filters never got dino-bombed (no light - perpetual black-out!) and are still living filters full of sponges and other filter feeders. My BTAs in the past have done rare instances of sexual reproduction despite being in a nano. This week I saw a couple of brand new, tiny BTA babies that seem to have come from such an event. I also have a population of hitchhikers limpets that I thought had been wiped out by the dinos but is actually starting to rebound, and they have been growing really well. It takes a healthy system even if a hiddeous algae mess for both of those things to happen, so I feel like that means I'm finally in the clear and can start to rebuild.

There are no decent saltwater shops left anywhere near where I currently live, at least not where I can get healthy CUC-type inverts to start fixing up these tanks, so I finally just mail-ordered some CUC before the temperatures drop too much. Wish me luck.

If anyone else here has dealt with an aggressive variety of dinoflagellates by some means other than just throwing in the towel or doing a risky chemical bomb, I would be very interested to hear your story.

Donya · Oct 26, 2024

Well, 3 days to snails and crabs.

Don't ask me why I feel like I have to tidy up for this event given that CUC means "clean-up crew" and it's literally their job to have at the algae mess. I guess I just needed to prove to myself that there's still promise under the thick sludge that likes to grow on the glass in the total absence of a CUC.

This pic is completely pre-clean on the coral tank that was hit the worst and had the longest recovery. There were 3-4 different species of algae in this interesting surface scum. It was rich in pods but I need to be able to see what on earth is going on in there once CUC is in, so surface goop had to go even though it was part of what helped me defeat the dinos.

This pic is after cleaning a swath on the glass to just barely see in. Those white finger-like things are sponges. They're all over the rocks. I'm sure they will mostly get eaten by the impending CUC, but I nevertheless thank them for their job filling the ecological gap for such a long time. They will live on in the canister filter where the CUC can't reach.

And post tidy-up. The result is actually somewhat less awful than I was expecting. Can't clean anymore though or I do risk destabilizing things again without critters to help me out. I have a few more things to prep for CUC arrival and more water to mix and heat to have on standby, but hopefully the critters will arrive safe and will enjoy entering a land of food.

Donya · Oct 29, 2024

The CUC invasion has landed and is doing well so far. No thanks to the courier - the driver left it sitting completly hidden from view of my house at the bottom of a long driveway with a bend and didn't update the tracking for ages - so it was sitting out in the cold for a while before I even knew I needed to go looking for a box in the leaf piles. I normally have quite a bit of respect for delivery guys, but it feels like this guy deliberately tried to not make contact. Not even talking about going all the way up to the house door - my husband and I were outside doing work at the top of the driveway when he came through. If he'd gone even just 10ft further up, we'd have been able to see him. We thought we heard a truck stop and went to look but didn't see anything - but I wasn't looking for a small box just left randomly in the foliage since it was supposed to require a signature. He would have been able to hear us working outside. The box was marked with all kinds of warnings about how fragile and thermally-sensitive the contents were. Really annoying. Just glad everything survived; it could have gone a lot worse.

Hermits and other crabs are in the coral tank, which currently has algaes that need a somewhat more aggressive touch. Snails and everything else is in the anemone tank for now, crab-free. I may swap some around as the cleanup progresses.

When you're so desperate to get to eating that wall of scuzzy food that you forget you're still sitting on the human's hand...nom nom nom.

A small urchin who will be filling the rock-scraping roll for rouher algaes that snails struggle with. My Echinoderms were never affected by the dinoflagetllates. I did lose my last old urchin recently, but it was after the dinos had already been beat; that old guy was around 8 years old I think (maybe even closer to 10...I can't remember exactly), a good run for an urchin. I hope this one can have a similarly long run.

One of the funny little Limpets that have been repopulating in my tanks. Quite the hairdo on this one.

Also...extremely rare photo of Scrooge McFish, my humbug damsel.

Naughts · Oct 30, 2024

I hope everything continues to flourish and you can post more photos. I love the little crab on your hand.

Donya · Oct 30, 2024

Interesting problem I may have...these are two of a collection of Astreas that were in the pack. Note that one on the right looks a litle odd. That's because it's got two rather large limpets on its shell! (The other one also has a friend: a Vermetid snail hanging off the side - but I welcome those as a hitchhiker)

Those are a completely different limpet species from the ones that are breeding in my tanks. These two limpets haven't moved yet that I've seen, although I only just noticed them, so perhaps there's time yet. I'm a bit weak on knowledge of limpet species but I do know that some basically don't move after they reach a certain size, and then they grow their shell pretty flush against whatever surface they're attached to, almost like the way some clams work. That kiiiinda looks like what might be going on with the bottom one since the fit is awfully good with the shell shape, although definitely not as much for the top one since I can see some shell rim hanging off. There are some in the Long Island Sound I used to see that are stationary - they are motile early on and then try to clump up around each other to be able to breed, but otherwise can't move and die if dislodged. They often ended up in limpet chains that would get break free when the bottom snail died, and then they'd wash up into a tide pool where I could look at them. Anyway...if these limpets are stationary and were on a rock or empty shell, it'd be a non-issue...but on a live snail is potentially a problem with how big they are relative to the snail. Also a worry if I try to remove them whether the shell is in proper shape under them. A very, very long time ago I got a conch that turned out to have several of some kind of parasitic limpet on it, each of which had bored a pinhole underneath it through the conch's shell and had a long probocis through there into the host's tissue. So, when I removed the limpets, the host died too after a few days. Ah, I forgot how much marine life is all smiles and rainbows! :lol:

Anyway...so if these don't move, then I have to decide whether to pry them off or not. For now I'll leave it but I need to try to ID those things to know if they're just a nuissance freeloader on that one snail or if they're acctually doing something more nefarious.

Everything else is going really well. It's really rewarding to see healthy inverts motoring around once more and they are making good headway on the mess. I did end up moving some snails over to help with the glass in the coral tank. Aside from the snail, here we have a crab and two hermits taking a short food coma break before getting back to work.

Donya · Nov 4, 2024

Well thank goodness - false alarm on the limpets! They appear to be some kind of Crepidula. What an awful genus name really lol. Anyway that means they are quite closely related to the ones in the Long Island Sound and I'm doubtful they'll actually last that long in this tank so I will just leave them be. Most likely they'll fall off of the Astrea in a couple months or the crabs will pick them away.

As far as tank recovery progress, the reef is showing some good improvement with a one-two-punch from the CUC and me siphoning out what they rip off of surfaces and leave to drift around the tank. Those cabbage leathers don't even look real at night. And yes that is a box of frags on the left. I have a plan. I do. It's not just poor impulse control and trying to beat the impending winter weather halt to shipping stuff.

These are the frags. Two of those are pulsing Xenia which actually make a great nutrient export and rock cover if they like the tank. These seem to like the tank so far so it's looking promising. If the CUC can clean new turf and these guys can overgrow it...less foothold for nuissance stuff. I have used Xenia this way with success in the past, it's just a big finick on initial introduction into the tank. It either likes it or it melts and so far it's doing its wavey hand thing and not melting. As for the tree coral...yeah ok that one was just because I wanted it and they're hardy. I think I got a bit ripped off with that one. Perhaps I'm just spoiled by the insane levels of green on those cabbage leathers I've had for 14 years but, personally, I would not call that tree coral a "neon green" tree coral as it was listed on the site.

Hazards of buying stuff sight unseen online I guess. Maybe it'll green up later...probably not though. At least I have good hopes for the Xenia having a niche in the tank.

Also, now in snail and anemone land...which I guess I will just start calling my urchin tank now.

Donya · Nov 7, 2024

Reef tanks are wild - I just found some crazy bivavlves in the back of my coral tank. There's been nothing into these tanks in years that could have added these. I had no idea they were in there. Last bivalve I knew was in that tank was a mussel, and these new things certainly aren't that! Here is one of them, it's the weird looking blob next to the big empty snail shell. You can see one of the siphons is open.

I saw evidence of new growth already on the Xenia frags, so time to get out of the side bin and into the main tank for the frags. Both Xenia frags seem really happy. Can't say the same of the tree coral frag in the back...that one sulked for a solid two days after it first arrived in a box, so it will probably sulk for another couple days now...

Donya · Nov 8, 2024

Well...sadly the purple urchin may not make it. It turned up with a body injury that has now rapidly turned into an infection that's spreading really fast. It's still active and eating well, so I'm spot-feeding it nori to give it a chance, but I'm not optimistic with the rate the infection is gaining ground. I have seen urchins recover from serious injuries but it's always hit and miss. A long time ago I had an urchin that recovered from having a whole section of its body knocked out - so it was shaped like an orange missing a slice after that but lived for many more years and even grew new calcareous skeleton and mini spines in the concave area. But...I also had an urchin die from falling off the glass and getting jabbed by landing on one of its own spines badly.

It's possible the purple urchin's injury was from trying to force between rocks in my tank, but also possible it was from the box being dropped badly at some point in shipping and it just took some time for the infection to take hold at the site of damage. There was a snail in the same shipment that had trouble for several days and kept falling off the glass and trying to climb up again, which is a classic sign of injury in snails, although it eventually recovered. There was no discoloration or anything suspicious on arrival for the purple urchin except one tiny area where the spines had been slightly damaged, which is common...but when the body is damaged from something it can take some time to be visible. That little area of broken spines is where the infection set in first, which suggests the body was probably damaged there too and I just couldn't see it.

On a happier note, the pencil urchins are doing well. Everything else in that tank is thriving so far and the cleanup continues.

In the coral tank, the tree coral frag opened up sooner than expected. And...it actually is starting to get kind of a silvery blue-green sheen in places. Just a bit. Huh.

And another happy clam dude.

Donya · Nov 11, 2024

I do love pulsing Xenia.

I don't know if it's the Xenia growing or somethig else, but something is suddenly sucking the carbonates out of the coral tank - and that's even with a slow-release buffer block in the canister filter that I periodically replace (same thing in the other tank and KH is good). I'm actually having to do alkalinity dosing for the first time in forever. Could very easily be the soft corals doing it (some of which aren't that soft due to the density of their sclerites). Beating the remaining nuissance algae requires keeping the KH up, so I'll have to stay on that.

Donya · Nov 17, 2024

Keeps getting cleaner every day! The next battle that's buliding up is cyano as the hair algae is starting to struggle. That too will be gotten under control in time. The Caulerpa prolifera is picking up a lot of the slack too as I hoped it would; I've trimmed so much of that stuff since I started this process. Basically every strand in this pic is new growth from the last two weeks.

And this little purple dude has been making an amazing recovery. I was really not optimistic about him a couple weeks back, but he's vastly better now and still going strong. He's been willing to eat dried seaweed from a magnetic clip the whole time, so I've just been giving him a daily snack. The discolored areas have been healing back to normal and he's regrowing spines at a good rate.

Donya · Nov 25, 2024

Why just eat your food when you can wear it too? ...What...you've never felt the urge to slap a sandwich on top of your head and go about your day, occasionally taking it down for a bite?

Donya · Dec 14, 2025

I feel like I'm rubbish at full tank shots but wanted to put some updates on this thread, since I've looked at many woes-of-dinoflagellates threads and few actually show long-term management.

The reef as it is today. Unfortunately neither the Xenia nor the duncan are still around. The Duncan got toasted by the Lepastrea shortly after my last post. The Lepastrea apparently has sweepers; I thought they were a safe one for that...oh well. Now I know. The Xenia was booming and then...did what Xenia often does and suddenly shrank up and tossed little miniaturized polyps all over the tank, only a few of which still remain where I can see them. I assume it got out-competed for nutrients by something else. Since my last post from last year, new things are the green Sinularia finger leather, the blue sponge, fan worms, and most recently a bit of GSP. Also two new fish. Coraline, cyano, and hair algae come and go in small amounts here and there. I always try to run my tanks a bit on the scuzzy side for faunadiversity reasons (now with the added motivation of dino-prevention). One equipment addition on both tanks is a nano HOB skimmer that can be active or not depending on what's going on with the tank at the time; when it's "off" it's functionally just a HOB filter - really a very handy piece of kit, although not the most silent contraption.

The anemone/urchin tank is ticking along well too. The rock is all clean with crevices full of sponges, while the sides and back are urchin grazing territory since I never scrape them.

It's also worth noting that the dinoflagellates are not really eliminated...just pushed back in an acceptable ecological role. They are still there, if one looks hard enough. I finally started doing some microscope stuff with these tanks. I also now have a much better handle on easier ways to control them should they crop up again.

I believe Prorocentrotus was my main foe the first time around. They either get trapped in hairy stuff or like to hang out there, I'm not sure. They're never moving around much when I find them under the scope. This bunch were in some filamentous algae.

I believe this is a lone Ostreopsis next to an out-of-focus diatom. I had a very brief but obnoxious mini-bloom of these for a few days when my canistr filter broke. Wouldn't have known it was dinos though were it not for looking with the microscope though; it just looked like bacterial bloom.

I think these are some kind of diatoms. They are quite abundant in both my tanks.

Donya · Sep 12, 2026

Thought I would post an update here, since things have shifted in a very interesting micro-fauna direction for my reef nano tank. There is an important lesson learned that I want to share. Quite a number of things happened to my reef tank since my last post:

Intermitten mini dino blooms were eventually replaced by cyano. No blooms were big enough to kill anything, just made more work for me cleaning it up. (Worth noting my anemone tank was *fine* - that just adds to this whole series of stuff being weird)
The cyano blooms were almost worse to deal with than the dynos, but at least it wasn't poisoning anything. I started to get really down about the reef tank again but kept at it.
I realized I was running on almost no sand bed - so I very very carefully built that back up to about 1" where it should have been (as tanks age, they can "eat" their sandbed...this one definitely did)
The deeper, healthier sand definitely helped...on the sand. That's it lol. The cyano was still intermittently out of control everywhere else.
In a panic, I tried Tropic Marin's Cyo-Control. It worked! Until I did a WC. Repeated that a few times, same result. Highly suspicious.
Changed salt mix brands.
All it took was one big WC and everything started going right with less and less work required from me, and a couple months later the cyano is so reduced I don't even worry about it anymore. I still have some nuissance algaes in spots but they are receeding as well with no extra work from me.
~~Developed a Palythoa addiction~~ ok maybe not exactly relevant here but there's a lot of them in there now

So, the important lesson I've learned: just because a salt mix brad used to be good doesn't mean it always will be. I was so resistant to considering that because I have been an Instant Ocean user for around 20 years. You use something that long with success and you really do want to look for literally anything else as a culprit. Nothing ever tested of with it, and I tested a LOT. But results are results. So goodbye, Instant Ocean brand. Hello to Two Little Fishies salt mix - which has a version in little packs suited for 5-gal jugs so you never have to worry about the remaining salt turning into a massive brick unexpectedly if you don't seal it up properly. I need to break my microscope back out and have a look at what the microbes are doing becuase this is SO different of a reef experience now. Holy coraline algae batman.

Corals are thriving. If anyone wonders where that big green goober of a leather coral on the back went...fragging is where it went. It was overdue. It's currently in a tub being grouchy and stinky as leather corals do when fragged, but it's healing up and getting attached to some rubble. Got a new magentic shelf set up in the back to put something else in that spot eventually. Might mount some things on the sides too since I have always found those murder to scrape compared to the front.

Oh, and that little tree coral frag where I was going "wait this isn't green" and was grumbly about it because I thought it had been falsely advertised...uh...well it's actually quite a beautiful electric green now when the light hits it. Was it the salt? Does it just take a million years and only get this color when big? I have no idea. But it's green now.

I am loving how well my corals are doing, including that gorgeous blue/sliver Xenia. Overall I still consider this progress after changing salt mixes a HUGE win. But, it's never all positives. Now for the crummy parts of that fauna shift. Something in that crummy Instand Ocean mix was obviously feeding two things that I was rather attached to:
- My Caulerpa prolifera
- That cool blue sponge

My macro got starved out of existence, and my blue plating sponge, which is photosynthetic (not a pure filter feeder) is nearly gone too. In such a small tank I'm not about to try dumping fertilizers or similar stuff in when everything else is doing so well, and those two things started shrinnking so fast after changing the salt that I just kind of had to accept it. I tried some other species of macro - they got starved out too, and rapidly. Whatever was in that old salt mix feeding the macro and sponge isn't something that I have a test kit for, so I may never know what the actual chemical difference was. I did manage to save one tiny piece of the prolifera macro before it completely left the reef tank and moved it to a container inside my anemone/urchin tank...briefly. I tried very hard to keep it protected. My urchins had other plans. So for the first time in many many years I am completely without macro algae in any tank, which feels weird.

I'm not going to fully give up on macro. It's fine if my reef no longer supports it, the nutrient export is happening through other things - but I want a little seaweed forest again. Somewhere, even if not in the reef. Can't do it in the urchin tank because urchins. So, I'm going to try a new tank with macro and the new salt mix where I'm not worried about dumping in some nutrients to experiment with that it needs. To this end, I dusted off a very old 1.5gal for a leak test and my husband responded with actual disappointment that I was going to set up something so tiny. I'm sick at the moment so I'm not going anywhere for a while, but as soon as I can actually go somewhere I guess I will be bringing back a shiny new tank for the first time in a decade.