Why do fish swim up and down glass

[Lilly Moore]

Why do fish swim up and down glass

 

[Danroo]

are they doing constantly?

 

[Tamberav]

Cramped/stressed or sometimes they just want food.

 

[Coxey81]

Why do fish swim up and down glass

Usually I think it's been determined because they may feel cramped.

My six line wrasse did it my 40G for about 3 weeks or so. Then he finally chilled out and just circles in an out of the rocks.

 

[Coxey81]

Why do fish swim up and down glass

Usually I think it's been determined because they may feel cramped.

My six line wrasse did it my 40G for about 3 weeks or so. Then he finally chilled out and just circles in an out of the rocks.

 

[flagg37]

My clowns would do it in my 120 gallon. I don’t think they were cramped. I think they were just dumb.

 

[davidcalgary29]

My filefish does this at night, and usually while sleeping: I note that sometimes it "falls" straight down, startles itself, and then swims back to its sleeping spot. I had to move my MP10 as it "fell" into the powerhead a couple of weeks ago, got plastered against the intake, and jumped to the other side of the tank. Maybe fish do dream and it had a nightmare!

 

[homer1475]

My melanarus does this, no idea why. He either paces the side glass(only the side the TV is on) or does laps around my MP10(up the glass, 5 or 6 laps around the MP, then back down the glass).

99% of the time hes cruising in and out of the rockwork. I've noticed he does this mostly at night just before he goes to bed. Nightly exercise?

 

[Mr Cypher]

My fish do this as well have a 100gal but with mine I think they are looking at their reflection my yellow tang will try to fight his reflection in the glass daily lol

 

[i cant think]

My CBB did this a few months back (Maybe last year in June actually). It was always along the side with the tank right against the wall, and the foxface did it too. They weren’t cramped - They behave normally now and I have come to realise they saw their reflection and went either defensive or courting mode.

 

[Crabby48]

Most of my wrasse did it when transitioning to male. Thought it was to use their reflection for dominance idk. My potters wrasse did it for a year before he stopped

 

[Idech]

I think stress is the most common reason. Fish that are acclimating do it a lot. Or fish that have no place to feel secure in the tank because they are being harassed or the aquascape doesn’t meet their needs.

It’s the equivalent to a human in a room that they can’t leave, staying close to the door to be ready to make an exit when they can.

 

[Mr. Mojo Rising]

I think stress is the most common reason. Fish that are acclimating do it a lot. Or fish that have no place to feel secure in the tank because they are being harassed or the aquascape doesn’t meet their needs.

It’s the equivalent to a human in a room that they can’t leave, staying close to the door to be ready to make an exit when they can.

I think we can only guess since no one speaks fish, but this would be my guess as well.

 

[Paul B]

They want to get out. Normally fish swim a lot farther than they can in our little tanks. Usually hundreds of yards around the reef. Then have no idea what glass is and they can see through it as they can not see their reflection as we can't when looking through a piece of glass.

They see this big open space including your kitchen and maybe want a banana. Either way, they want to get out and don't know why they can't get there.

 

[Lyss]

Tons of good responses already.

It’s always one of the below, but you need to figure out which applies to your particular situation:

New to tank — will stop once settled

Cramped/tank too small

Boredom/tank too barren, not enough caves, etc

Flow too strong — I had to make a baffle on my FW tank b/c the dwarf puffers didn’t like the flow

Seeing reflection, or light pollution at night

Water quality going south

 

[MrTPlush]

I mean, it’s like an invisible wall. With a fish brain I think some just never grasp the concept of that being the end.