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Nov 5, 2019
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Hello! I have a common pleco in a 29 gal (along with just 1 female Betta because I have a sorority but she was too aggressive for everyone else but she's been good with Tom the plecosTOMus) anyway, recently Tom has been acting really odd.

At times he will be super still, not even sucking on anything just sitting on a rock or gravel looking almost dead, except he blinks. Other time, he rubs his nose on the glass really violently (see video)

I do 10% water changes every week, and I have a heater that keeps the tank around 78°F. I pretty much only feed him algae wafers.

The only thing that I could think that it is is that recently, I had a snail problem and I read that to get rid of them, don't give them anything to eat (like algae) so, I took all the rocks out,a scrubbed them,p and them in a bucket and put algae killer in the water and let it sit for about a day, then rinsed them and put them back in the tank. Since then, I haven't kept the light on for as long in the day and my tank has been pretty clean ever since (again, see video). Could it possibly be too clean? And could the algae killer have soaked into one of my rocks that is pretty porous and be hurting my pleco somehow?

The normal solution for fish problems is do a water change but I'm worried that that is actually my problem, is that logical or am I off? Lol please help!

Also, I know plecos get big and eventually I am going to have to either get a bigger tank or give him away, but for now he has more than enough room to turn and swim around, I don't have to make that decision quite yet!

Oh! And one more thing, I've seen on other forums that a lot of people ask if the pleco has enough caves to hide in, and he pretty much only has a coconut that he usually loves to hide out in. Besides that the rocks don't really make caves, should I make more caves for him? Could that be stressing him out?


Photo of tank:

Hopefully those links work! Let me know if they don't I will try to figure out another way to share them

Thanks for your help in advance!!
*just did a water test and it read....

GH- 180
KH- between 80 and 120
Ph- 7.5
NO2- 0
NO3- 0
Well I have a few varieties of similar Pleco's (do you know what kind of Pleco this is? Is it a Sailfin? A Trinidad?) Not all Pleco's are Herbivores - some are Omnivores - in any case he needs algae to eat so I assume you've been giving him algae tablets? There are also vegetable flakes. Omnivores would probably enjoy the sinking tablets - it takes them a while to eat them (not the "2 minutes you're told) - it may take them an hour or so - but you've probably already noticed that from feeding him algae tablets.

I don't think anything you did to get rid of the algae hurt him since you rinsed it well - but he likely would have enjoyed eating all the algae for you.

The one thing I notice that is very different from my plecos is that he's not sitting in a cave or hiding in a corner looking grumpy and still all day. This guy is super active - which mine never are if they can avoid it. If he lived in my tank he would have several choices of large caves (if you can find some slate rock at a pet store and get about 3 equal sized pieces you can build him the perfect cave- he's so big now it's going to be hard to purchase one. Mine stay in their caves all day and give me a very pissed off look when disturbed. I have to leave some leftover food at night (which doesn't help with the snails) because they only come out at night to feed. Other than my 2 Lemon Bristlenose (which are omnivores) and are very active, the others do not swim like that, they are the laziest fish I've ever seen. .One thing they do is spend a lot of time on rocks and preferably in a cave or deep within some foliage and just lay around all day.

He may just be hungry or he is desperately looking for a place to hide. All my tanks are planted, including having floating plants on the top of the water - it gives them a feeling of privacy. I'm sure he would LOVE a well planted tank with a big cave to hide in - but switching to a planted tank would take about 2 or 3 inches or more of substrate (sand or gravel - sand or a soft gravel would be best for a pleco) and a few fast growing plants. Lots of stuff floats and doesn't need planting, other needs to be planted - problem is most of the local fish stores plants are in terrible condition and likely to re-introduce snails into your tank. I'm like you - I HATE snails - just pulled over 1,000 out of one of my tanks the other day and I had only skipped 2 days pulling them out. Unbelievable but they do eat the excess food - which since I tend to overfeed has been a lifesaver but I just want a few not thousands (although I'm keeping the next red or gold one I find). If you have friends with aquarium plants - see if they'll share some of the overgrowth or if you have a small local fish store they may have a tank where they actively grow plants (I don't think the big retailers have quite as many growing plants, most are half dead in plastic bags). BUT switching to a planted aquarium is a big step. They are messy and attract snails but you don't have to water the plants or anything - they just grow! If you decide to do this, get a few plants and get some aquarium plant fertilizer - Seachem offers some - Flourish and they have these little tablets that you bury in the substrate that dissolve over time.

If you don't want to invest in plants - I would say he needs a big cave, because he's a big guy. In fact the cave is probably your first priority. He just is not comfortable being out in the open and looks rather frantic about it.

When I imagine Pleco's in the wild, I imagine them living in a cave in a rapid stream - catching things if they are carnivores or eating foliage if they are completely vegetarian..

And verify his diet - in case he needs more than algae.

Oh and water parameters usually include
KH and GH

Ammonia and Nitrates are fatal to fish - ammonia will burn the gills and just kill them so you always want your ammonia and nitrate level at zero. The other parameters are important when you set up your aquarium but aren't important on a day-to-day basis. As far as water changes - I usually do 50-75% once a week but I have a lot of fish in my tank. Your tank looks spotless - you might want to go to 50% every 2 weeks unless there is a build up of those algae wafers (they make a mess) - you can also just do a quick gravel cleaning if that's all it needs. But I am a fan of once per week water changes but in a much larger amount than what you are changing - while it doesn't seem to be doing him any harm just remember when you only change 10% you're leaving 90% of the "bad stuff" in the tank. If you turn out to have high levels of ammonia and/or nitrates you can neutralize them with a Seachem product called Prime. They'll still show up on your test results but if you bought an even fancier test kit you could see that the ammonia and nitrates have been neutralized to something that is not hazardous. But Prime and similar products only keep them neutralized for 48 hours so you'll want to add a capful every 2 days. The number one killer of fish is Ammonia levels. API makes a test kit that allows you to measure these parameters, there are also test strips that aren't as accurate and far more expensive in the long run. I test either every day or at least every other day.

Best of luck and get this guy a nice cave, I think he'll settle down and then you'll miss seeing him all the time!
Oh and if you do add more substrate you may want to seriously consider sand - some plecos like to bury themselves in the sand. But before you put it in your tank RINSE RINSE RINSE - with a fine mesh colander to get rid of the sludge in the sand or you're tank will be a cloudy mess. Seachem also makes clay gravel (and sand) but it comes in "dark" - which is brown and black which is very pretty. Even the clay gravel should be rinsed multiple times but you can use a larger hole colander since the particles are bigger. You want to rinse until the water runs clear and then one more time to be safe. Stir it as you rinse it.
Plecos need to graze on wood to aid their digestion. You should have some driftwood in there.
I concur with @seangee. Pleco need to have driftwood in there tank, so they can digest their food properly. The driftwood fibers do just that. I have 3 small/medium pieces in my tank with my Albino pleco, and he does just fine. Good luck! :)
Thank you so much @Jan Cavalieri ! I really appreciate you taking the time to respond

Based off of pictures, I think he is a Trinidad! Which helps a lot since the pet store just called him a common pleco, and I had never heard of Trinidad plecos before, so when I tried to identify him based off of the types I was aware of, he did not seem to match up to any of them. I also thought all plecos were herbivores, but Trinidads are omnivores so that is definitely very good to know! I will definitely adjust his diet.

I will definitely start by making more caves for him, and consider live plants as well! thank you for the advice on that. I already do have some sand in the tank, it just always finds its way underneath the gravel, today when I re-scape my tank I might try separating an area that just sand for him now that I know he will like it.

Also, when I do water changes it's with a gravel vacuum so even though it's only 10%, I feel like I get most of the poop and stuff from the bottom. Maybe once a month I'll do about 50% water change. Would that still be adequate in getting the "bad stuff" out? I might switch to the schedule/method you suggested.
*I think I will be okay using natural drift wood as long as I boil it first.
*I think I will be okay using natural drift wood as long as I boil it first.
NO. Do not use driftwood from a local river and think its safe just because you boil it. ONE you need to identify the wood as some of the sap/tannins from the wood are poisonous to fish depending on the species of tree. Two, you have NO IDEA what could have soaked into that wood from things being dumped into the river like human waste and other chemical waste. THREE, boiling sometimes kills most parasites but not all, and doesn't release all if anything the wood might've absorbed for however long it was submerged.

Go to your local petco or petstore. They sell mopani wood in various sizes, the small ones ranging about 7-10 dollars a piece. Mopani wood has the benefit of sinking immediately as its a heavy wood, but it will release tannins into your water and tint it a tea brown. Tannins wont hurt your fish from the mopani wood, I personally think the color adds a more natural feel to the tank. My two BN's I'm raising to be mates for my female in my main tank love mopani wood, even the cholla wood I threw in there.

Don't be cheap and get the wood "decor" from the lizard/reptile section. Those woods tend to be treated and the most common is cork which never sinks and I've read grape wood can be dangerous. Stick with mopani, or other species like malaysian driftwood, cholla wood, or spider wood.
I concur 100% with @FroFro, just buy it from your LFS (Local Fish Store). At my LFS I can choose how big I want my pieces, and they will cut it for me. :)

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