After 7 months of healthy fish, total die-off. Help!

[Ccga]

I prefer the larger true floaters. Small plants like duckweed can be useful at removing organics/nutrients/ammonia, but they can be rather a nuisance in many tanks and have no "substance" to speak of. A slightly larger but still small floating plant is Salvinia; S. natans is sometimes seen, this is a bit smaller than the truly lovely S. molesta which is probably the correct name for the larger species though it may be seen as S. auriculata that will be the same. Salvinia is a small floating fern, the sole genus in the Salviniaceae family. It consists of three leaves, two floating and one modified leaf submerged that may be mistaken for a root; the stem is branching and creeping, bearing hairs but no true roots. The larger S. molesta has a beautiful silvery sage green sheen to the leaves.

Moving on to more substantial plants, Ceratopteris cornuta (Water Sprite) is probably the nicest. This is also a fern, and there are three species, with C. cornuta being the best floating. This plant will spread its fronds (leaves) to cover the surface of any aquarium if allowed to; daughter plants are produced rapidly on alternate fronds so it is easy enough to remove these as new plants during a water change and discard the larger parent plant. I've been doing this for more than 20 years now, all from a single purchased plant, and I have this plant in three or four tanks. Not always easy to find, but well worth it.

Frogbit is another good floater; there are two temperate species that do not do as well in the aquarium as the true tropical species, Limnobium laevigatum, that comes from South America. I bought a very poor decrepit plant that was labelled the Amazon Frogbit some years ago, and it turned out to be one of the temperate species, identified when it flowered shortly thereafter. It has managed in a couple tanks since, though not as well as I expect the true tropical species would, with the continuing heat.

Another similar is Water Lettuce, Pistia stratiotes. Sometimes one sees a "dwarf water lettuce" but this is only small plants of the species, as there is only the one. Interesting roots when it is happy; I have them extending right down to the substrate in a 20g tank.

Some stem plants make good floaters, Brazilian Pennywort (Hydrocotyle leucocephala) being my particular favourite.

Byron.

Thank you. I think I'll have to travel around as where I live there is only one lfs and this doesn't have very much so I think I need to find a specialist in the SE England.



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[Aquatony]

Is there a cap on how much plant life a tank can support? Like, if I got a large Pennywort plant (one of my faves too) and a Java Fern, would there be sufficient nutrient support in the tank?

 

[StevenF]

Just a note that adding sea shells to your tank or in you filter will help protect you from future PH swings. The sea shells are calcium carbonate and it doesn't dissolve when the PH is above 7. So normally for you the shells wil have no affect on your water. However if the PH suddenly drops the shells will start to dissolve, neutralize the acid push the PH back up. This will increase water hardness but normally it is a small increase. You typically would need extreimly acidic water to get very hard water. The shells will normally prevent the water from geting that acidic. The regular weekly water change would then insure that the water hardness stays reasonably stable. Plants can also utilize calcium when they grow.

 

[Byron]

Is there a cap on how much plant life a tank can support? Like, if I got a large Pennywort plant (one of my faves too) and a Java Fern, would there be sufficient nutrient support in the tank?

Nutrients occurring naturally (meaning, no plant additives are being used) come from water changes and fish food. Technically, these are all plants need, by which I mean that the fish food will supply all necessary nutrients in terms of the nutrient. But obviously this may not be sufficient for the plants, depending upon the species and numbers of plants, as well as fish load and feeding.

There are members here who have fairly thick plant growth in tanks with little or no plant additives. I have a couple tanks where this is close to the case, and it is because of the higher organic level.

Light factors in to this too, because it is light that drives photosynthesis, which of course is how plants grow. The more intense the light, the more plants will grow, sort of...it then depends upon the necessary nutrients being available in sufficient quantity to maintain this growth. As soon as something, be it light intensity or a nutrient, is missing or insufficient, photosynthesis will slow. What botanists term the law of minimum, because it is the minimum factor that basically determines plant growth, not a maximum.

Some plants are faster growing, and these require more light and more nutrients. So Pennywort will need a bit more light, and more nutrients, than Java Fern. All stem plants are faster growing, as are all floating plants.

Byron.

 

[Aquatony]

Byron,

I spoke to MarineLand, who advised that the light does not produce RGB light, and is white LED only. So good to know.

Thanks for everything! We are going away for the weekend and have no fish in there right now, so we'll see what the cycle looks like after we come back.

Good to know this light is useless (more or less) for plants. Explains a lot..

 

[Aquatony]

An update.

So I have not had fish in the tank for a week. There has been plants though.

I checked my water parameters this morning and everything looked good. The smell test was good also.

I bought 4 Serpae Tetra who looked very healthy today. I very slowly acclimated them to the tank using the procedure mentioned above.

3 hours after placing them In the tank and watching them, they seemed very healthy, so I went to work.

My wife came home and found them all dead.

What happened? This water just must be absolutely toxic to so quickly kill these fish who appeared very healthy.

It doesn't add up.

Any thoughts?

 

[Byron]

Is this still the 10g tank? Was any water changed other than a week ago? What specifically are the test results, for what ever tests you did?

BTW, this tank is not large enough for Serpae Tetra; this is a rather feisty fish, prone to fin nipping, and needs a group of 8+ which means a 30g tank. I wouldn't replace this species. We can go into suitable fish later.

Edit. I have to sign off in a moment, but something else occurred to me while waiting for these results. When the kids dumped the food that started this all, is it certain that nothing else entered the tank?

 

[Aquatony]

Yes still 10G.

I checked for pH, NO2, NO3, and NH3.

pH was still 6, as we discussed. NO2 nil. NO3 5ppm, not a strong reading and finally NH3 nil.

I spoke to my LFS also today, who said our area does indeed have very acidic and soft water.

I understand about the Serpae. Unfortunate... Because I love their energy and their color. But of course whatever is best for the fish. Which is why I really need to get this sorted out.

Should I just tear it all down and wash everything with DI, and do a new cycle?

 

[StevenF]

This all started when you vacuumed the volcano. I would suggest removing the volcano from the aquarium. I would assume the volcano has an air stone in it. Anything else like a light? Is it plastic or some sort of rock?

 

[Aquatony]

Steven, yes there is an air stone type contraption. Could there be an intermittent electrical short? So not even toxic water. Electrified water? Yikes?

I always turn everything off when I delve into the tank as I've been taught to do by my mom who was big into this hobby for decades, so I'm safe... but maybe not the fish?

There's no light, though, there is plastic.

I got the volcano from Foster-Smith so I would hope it is safe. It's about 7 months old.

I did take the volcano out for a time. I caved in to my kiddo who really likes the aeration sound at night. So I think I'll take the volcano and such out.

But that doesn't really help me know if the tank is safe. This obviously goes beyond water parameters per se, as they test more or less okay, with two different test kits over multiple samples, it's always the same.

So no problem with taking the volcano out for good.... but then what.

 

[Aquatony]

Byron I just saw your edit asking me about anything else getting in the tank.

I kind of thought perhaps the kiddos improperly washed their hands and maybe some soap got into the water. We do not use Triclosan laced soap, so no anti-bacterial agent in it, but it's nonetheless a surfactant.

I've done very aggressive water changes though. Aside from some soap contamination... what are you thinking? I don't see with my eyes anything in the tank that shouldn't be. And I've definitely gravel siphoned every square inch of the tank in the last couple weeks...

 

[Byron]

Anything that might have entered the water wouldn't necessarily be visible. It was just a thought. The relationship of a fish to the water environment is so much more direct that any land animal to air.

I would do some total water changes, draining right down to the substrate. Removing the volcano might help, no idea really. Plastic is not a good thing to put in the aquarium, as submersed these can sometimes leech toxins. I too would expect to be able to trust Fosters&Smith, but still a possible.

On a similar track...what is the substrate composed of? And is there any other decor (wood, rock, etc) besides the volcano?

Another thing...can you ask the store if they do anything to their water? I have stores in my area, and good stores, that treat their water, buffering it to maintain a GH and pH closer to "average" (for lack of a better word, but you get the idea). Wondering if more acclimation might help, if they do. It shouldn't be this drastic, but one has to check every possible.

Diagnosing fish problems and sudden death can be very difficult. The extremely close connection of fish to water I mentioned earlier is why even the slightest thing can cause trouble.

 

[Aquatony]

Byron,

I will do a total water change. I also planned to use distilled water to scrub down the decor in the tank.

The gravel is from Petco, and is the same exact gravel my best friend uses in his 30 gallon tank, for years. It is aquarium-designed. And was in the tank for months before this die-off occurred...

Since there is mature filter media (Biowheel) I suppose I won't need to re-cycle everything.
But, my question becomes, after I do a total water change and clean down to the substrate, and clean all the decor, how do I know it'll be safe for a fish?

I went ahead and bought some ammonia at the supply store in the event I need to just recycle everything per the forum cycling sticky.

 

[Aquatony]

OK, so check this out.

My pH meter finally arrived.

I rinsed with DI, calibrated it using 3 different buffer solutions to ensure precision, and tested tap water. That was 8.60, dead on from what the water co. says it should be.

Now when I tested my degassed tank water....

In case you can't read that. It's 2.91 pH.

So....... now what... wow!!!! How is it even possible?

 

[Byron]

I will assume this pH meter (something I've no experience using) is accurate. The pH is probably the issue, as 2.9 is too low.

I think I previously explained why the pH is lowering in the tank. The source water has no GH or (more especially) KH to buffer the pH, so when organics accumulate as they do in every aquarium, here the pH will lower as the water acidifies. The pH would be very acidic, if the water authority wasn't adding something to raise it. I have this where I live too. This is probably something like soda ash, which doesn't buffer or last long.

Steven suggested buffering options in post #18. I've not used shells, and I'm not saying they won't be as good. But as another option that I have used and it works...get a small (very small, it doesn't take much and it lasts for years) of aragonite gravel. CarribSea make this, there are probably others. Make sure it is just aragonite, no salt as will be in their marine aragonite substrate. The gravel is better than the sand here, in my experience. You add a small amount, maybe 2 tablespoons, using a nylon mesh bag in the filter, or you can hang it in the tank in front of the filter return if no room in an external filter. I do this in one tank, and it keeps my pH around 6.6 instead of at 5 (or maybe lower). I used to do this in my larger tanks for years, using dolomite. Aragonite is much the same, it is calcium and magensium, and it does a better job of buffering than crush coral or similar.

Assuming the pH is this low, pH shock was likely the issue. I would expect the store does buffer their water, and when the pH difference is this great, it would take a lot of acclimating, not just a couple hours. But even so, the fish will not do well at so low a pH regardless of being acclimated.

Byron.