Upside Down Pleco Fish? Floating Top of Water?

Topic: I have a community 40 gallon Aquarium and my plecostomus is always upside down floating tot the top? I’m wondering if he is having a bloat problem or if he’s gulping for air at the surface or.. what his problem is. Has anyone encountered this with their pleco fish?


*Awarded Answer
Posted by Chris W: I find that a lot of plecos swim to the surface and appear to be upside down when they’re searching for food. Chances are your fish is very hungry. You have to remember that these fish are nocturnal and you should be dropping the algae wafers in when the lights go off. This way the other fish don’t eat their source of food. You should also get some high quality wafers. A lot of times they are terrible quality. I buy Omega One brand. Here is a link and picture:

Omega One Veggie Rounds, 4.2 Ounce Container
List Price: $9.29
Price: $9.29
Price Disclaimer

pleco upside down

Does any1 else have a weirdo pleco that loves to swim upside down? Or Oscars that love playing in the bubbles when u do a water change.. I think my fish r a bit special like the rest of the animals & humans in my life.
I had a Large Pleco that would swim upside-down to eat any fish food I put in the tank like a normal fish going to the surface….


When the pleco’s get larger they don’t eat algae any more they eat fish food.
I have never heard that or noticed it before but will keep a eye out now, I have noticed they don’t eat as much zucchini anymore.
When I bought mine the lady at the fish store told me that and I looked it up and sure enough it’s true.
Our Pleco looks like something is wrong with it’s tail, and it floats upside down on surface of the water. Is this normal, or is something wrong with him?
I’ve had my Dragon (my pleco) for almost 7 years and he’s survived bad water that killed other fish in my tank. They are usually tough fish. He parks himself in his garage during the day.
I recently rescued a baby 1 inch bristlenose. He’s finally starting to come out and be seen. I’m quite fond of him/her already. It’s grown a bit as well over the past couple of weeks.
EMERGENCY! Fish struggling to breathe…

Woke up this morning and first thing I noticed was my pleco upside down. When I got close to him he was still breathing, fat belly and colored normal. I then noticed all my rams and other fish were strangely at the top in a position begging for oxygen. Not sure exactly what happened over night.

Here what I do know:

– Did not loose power overnight

– Filtration/heater running perfectly fine

– I did a normal 25% water change + added my fertilizers yesterday morning

Water parameters:

– 78 F

– pH 7.0

– Ammonia/Nitrite/Nitrate @ 0


Magnaflow 360 Canister Filter up to 100 gallons (mine is 55 gallon) — I’m running without carbon. I heard it’s better for fertilizers I use on my plants. Not sure if this could be the culprit. Should I re-add carbon?


API Leafzone (twice a week)

API Co2 Booster (daily dose) I haven’t dosed today yet

API Plant Tabs (1 month)


1 – Angel Fish

1 – German Gold Ram 

1 – German Blue Ram

1 – Ghost Shrimp

1 – Blue Phantom Pleco

1 – Snowball Pleco

1 – Julii Corydora

2 – Bristlenose Plecos

2 – Panda Corydoras

2 – Amano Shrimps

3 – Sterbia Corydoras

7 – Electric Blue Rams

10 – Otocinclus Catfish

11 – Gold & Yellow Platties

13 – Male Cherry Barbs

Total: 60

As of now I have moved my Blue Phantom Pleco to my hospital tank. He’s doing well there, he’s sucking on the glass and moving around so he’s gonna have a chance (fingers-crossed)… as far as my other fish I’m keeping an eye on but hopefully with your help I can diagnose what’s wrong and treat immediately.

Will lowering my water below the filter head to create more oxygen also help in the immediate future? I dont seem to have an airpump I’ll need to go get one.
Yes lowering the water line below the return will create some surface agitation and should help oxygentate the tank but still recommend getting an air pump.
Same thing happened to me. I did a water change and filled the water up past the rain bar next morning my tiger Barbs were gasping for air I pulled water out below the rain bar and they were fine.
An air stone and pump won’t do much for surface agitation for gas exchange. You need something like a “current” , hence why lowering your water level would be the best option.
Cool, that will work the best. An air pump is really only good for sponge filters, and airstones are just for personal preference like a LED bubble wand.
My mollies & guppies always go to the top like this. But don’t get blotted. Does this mean i should have a bubbler also?
That’s good to know. I love little fish like them. As u can probably tell. I’m new to the hobby & ask loads of questions. Thank you for putting my mind at ease.
I have lowered mine a lil below the water line too. My tank  is way overstocked so I’ve seen my fish doing the same lately. Within a few minutes, there back to swimming all over.
So I have lowered my water level below the filter to oxygenate… it appears this is helping, now for the future.. what should I get or add to prevent this?
Keep the water level the same, even when doing water changes. This level will oxygenate your water and keep your fish happy.
I’ll start doing this. My fish seem fine but if i can make things better soon rather then later. It’ll b better all the way around. Man i love this group.
I may just get a bubbler today. I like the water high. Gives the front of the tank more of that window look. I really don’t like seeing the water line. Would the bubbler b a better way to go?
I have a hob filter. It’s fairly big for over filteration. Myself. I have a 60 on my 36 gallon. Wouldn’t adding another filter add to much current & same with a powerhead?
All my rams are back to swimming bottom normally since dropping my water levels. Does this conclude that my problem was lack of oxygen?
You should have some nitrate in an established tank nitrate should never be at 0 and if wasn’t said already do you have any top surface movement.
All I know is and I don’t know why but tanks should always have a form of nitrate in their tanks but everything else needs to be 0
U need some water movement and bubbles airdrome some thing like that

I personally have a homemade filter that splashes into the tank 

A little thrust power head at the water surface chopping the water helps also 

I have a 125 pretty well stocked and that’s what I have.

As long as you have a good filter and enough bio filtration which is the most important that and the water surface stuff we talking bout.
Oh, i think i’m understanding better. So if i got a powerhead. Should i drop down on my filter size? Will it also effect my danios? Their always at the top & will they all stay lower with the other fish if i had a powerhead?
Danios will swim in the current BUT they can get sucked in to it, I’d suggest a smaller powerhead, something to just move the water enough to cause gas exchange but not blow the water out/suck in fish.
I have a pump for a foutian. The air intake is inside of the pump’s case & just a hose sticking out the top. I’m gonna try to use that if i can get the outtake to open up more so it won’t just push a small line of water.
Oh… So it should b placed close to the filter. I’m not sure why i didn’t think of that sooner lol. Thank u so much. This is my first tank. The better i make it, the more i learn what the do’s & don’t r for my other tanks i have to set up.
Make sure your intake the sucking part of the filter is sucking and the out put the little square ended tune is blowing out 

I think if you move the square put to where it’s coming out the water a little bit and splashing it will do exactly what you want 

Just move it up some for water surface agitation.

They have powerheads that have an air tube above the surface that pulls O2 into the impeller and will create microbubbles throughout the tank.
It makes no sense that you’d have 0 nitrates in a cycled aquarium unless you do large water changes on a daily basis. I would test again. I really don’t think this is an oxygen problem.