Help! My Fish Plays Dead!

I have two plecco agae-eaters (ugly suckers) that are easily 6-8 inches in length, each. I check my fish every day, and last night I found one plecco backfloating at the surface. I thought for sure he was dead. (Pleccos cling to the sides and tank decor, but they don’t do that!) I even tapped on the glass to be sure as they are cowardly. He didn’t budge. As I reached for the net, he sprang to life and swam away! A few hours later, I found him backfloating again…and then swam away after a tap on the glass.

He’s about 5 years old now, and still full of life! But, does this mean he’s going to die soon? How long do these things live? And, how much longer will he grow? (FYI: I have a 40 gallon tank.)


  • Jinx

In my experience the end result of this behavior is a dead fish in the not too distant future.

Agreed on the “not long to live” diagnosis. Sounds like his swim bladder’s about to give up the ghost.

Another possibility is constipation and gas, but I wouldn’t expect that in a pleco that normally eats a vegetarian diet and probably pays no attention to whatever flakes you’re feeding the other fish.

They can hang on for days, when the swim bladder is bad. They float the instant they stop fighting buoyancy.

Check your water heater.

Mine did this, and he’s a 7-year-old BEAST; about 10 inches long, ugly as sin. Anyway, turns out my water heater had blown something and was no longer working, and when it got too cold he’d let himself float near the surface (where it was warmer, I suppose?).

Anyway, I replaced the water heater and he’s still going strong, a year later.

Edited to add: Cowardly?!? I must have the Rambo of pleccos, then. Mine tries to ram me with his spines every time I reach in to clean the tank. Pet store says this is normal and they hear about it all the time.

My uncle’s tank heater stuck on during the two weeks their family went to Florida. The Fish cooked, the water evaporated down, and the glass bulb broke on the heater when it was exposed in the air.

I’ve had plecos backfloat on the surface when they’re hungry. They know there’s food up there, that’s just not where they prefer to get it.

Are you sure he’s getting enough to eat? They make sinking algae wafers & such for them. They also like fresh veggies. You could try him on lettuce, zucchini, etc.

I would not depend on the algae & detritus in your tank keeping him well fed and healthy.