My bichirs are staying at the surface... Why?

[Stab]

The tank is a 55 and has been running with its current inhabitants for nearly 2years. It houses 3 eel catfish, african brown knife and my bichir collection: Common Senegalus, albino senegalus, palmas and an ornate. All ploys are between 6 and 8" in lenght. They are fed daily a combination of live black worms and sinking carnivore pellets by Hikari. Water temperature is 79F, and all parameters are fine. Decor went unchanged for at least a year and tehre are plenty of hiding spots for everyone plus a partial cover in the form of a few floating fake plants. Suddenly all of my bichirs seem to be spending more time at the surface rather than on the bottom. They seem to be perfectly fine otherwise, and this behavior does not appear to be a sign of boyancy problem -- they can go down just fine, and always do to feed. Any idea whats going on here?

 

[davo]

if you do a search, you'll find a lot of people worry when they do it, but if everything is fine... sometimes bichirs like to be by the surface, they do in the wild too. If they feel secure they sometimes do it. If your really sure everything is fine and they are healthy etc, i wouldnt worry about it. They tend to do it a lot when they are young too.

 

[whiskey]

I have some smaller peacock bass in the same 75 tank with my monster endi, sometimes the endi lays at the top of the water and trys to hunt them. It's kinda sweet.

 

[Stab]

I am not worried actually... Yes I know its not uncommon for them to swim/lurk at the surface. They just never did that before and I wanted to figure out what could cause this change of behavior.

 

[fivespeed302]

Let me get this right, you have 8 large fish in a 55? What do you do for aeration? Could just be a problem with aeration/overcrowding

 

[Stab]

Let me get this right, you have 8 large fish in a 55?

I do? LOL Actually I thought about aeration too. Still doesn't explain why they seemed to be unfased until 2 weeks ago