fish gather at top of tank

[Pete7]

Is there any reason why my fish all of a sudden gather in the top corner of my tank. Most of the time they spend the day bottom to middle, then a couple will go to the top corner and the whole tank follows. Ive got an acara, firemouth, rainbow and a small jack dempsey in with a few columbian tetra. Its started to happen a few times a day is this normal

 

[Gourami Swami]

If they seem to be "breathing" fomr the surface, you probably have low oxygen in the tank and need more flow/surface movement. If they are not breathing heavily up there, they could be looking for food. My fish all come to the front/top and beg whenever I walk in the room.

 

[duanes]

I agree with Gourami Swami, sounds like a lack of oxygen.
What size tank? What size fish?
Are there a lot of plants?
Sometimes during the day the plants will use carbon dioxide and give off oxygen.
At night with less light, plants use oxygen, which could bring the fish toward the surface, especially if there is a buildup of mulm metabolizing debris (also using up available oxygen).

 

[Pete7]

If they seem to be "breathing" fomr the surface, you probably have low oxygen in the tank and need more flow/surface movement. If they are not breathing heavily up there, they could be looking for food. My fish all come to the front/top and beg whenever I walk in the room.

They're not gasping for air and i have extra eheim filter that helps with flow, but i think you could be right about looking for food because they all dash up to that corner. Its just strange they all stay there for a while then drift off back around the tank

 

[Pete7]

I agree with Gourami Swami, sounds like a lack of oxygen.
What size tank? What size fish?
Are there a lot of plants?
Sometimes during the day the plants will use carbon dioxide and give off oxygen.
At night with less light, plants use oxygen, which could bring the fish toward the surface, especially if there is a buildup of mulm metabolizing debris (also using up available oxygen).

Ive only got a couple of plants in the tank, its mostly artificial the tank is 240l with a powerhead filter and a canister filter. My acara is about 5in, firemouth about 4in, jd about 2in n rainbow about 4in

 

[tlindsey]

Begging for food my Acara and other Cichlids do the same thing lol.

 

[Pete7]

Begging for food my Acara and other Cichlids do the same thing lol.

Haha yeah my acara is greedy to be fair n most of the time he's first there

 

[ragin_cajun]

If one fish in a tank goes up to the surface to look at something, every other fish in the tank will come up, too. They don't want to miss anything.

If a bug walks across the top of the tank, this will happen. If a water drop forms underneath the lid of the tank, sometimes fish will get captivated by it. Just hang at the surface right under it, staring. Maybe you have something stuck under the lid right there.

 

[Pete7]

If one fish in a tank goes up to the surface to look at something, every other fish in the tank will come up, too. They don't want to miss anything.

If a bug walks across the top of the tank, this will happen. If a water drop forms underneath the lid of the tank, sometimes fish will get captivated by it. Just hang at the surface right under it, staring. Maybe you have something stuck under the lid right there.

I never thought of anything being stuck under the lid or light inside the tank, will check it out. There is alot of condensation under the lid so it could of dripped into the tank attracting fish

 

[Toiletcar]

It's hard to say, there are a lot of possibilities mentioned. But a few others might be water params. Since they are gasping for air or breathing heavily, I doubt it's an ammonia spike. It can't hurt to check.
Another possibility could be water temps. When water is cool, I've noticed sometimes my fish will look to warm up near the light.
But I think the strongest possibility is looking for food. Is that area a typical feeding spot?

Anyway if I see a change in behavior I check everything to be sure.