Gibbiceps Blowing Bubbles

[discus dreamer]

Hi
my young gibbiceps (about 5 in) has suddenly started behaving differently. He is a bit skittish and will be attached to the glass then suddenly release two bubbles one from each side and then quickly swim to the surface as if getting air and then go back down again. I wondered if the oxygen was low in the tank so adjusted the outflow to agitate the surface of the water a bit. The only thing that is different in the tank is that i did give him some courgette the other day, he usually gets cucumber. Is this normal or the sign of a problem?
thanks
worried DD

 

[The-Lion]

Yeah it might be the oxygen level. I had the same thing when I 1st started keeping plecs in my juwel tank; I soon learnt it was an indication the filter was getting clogged thus reducing the flow & affecting the oxygen.

 

[discus dreamer]

thanks
I think the filter is ok, it is a big canister external filter and I did check it two weeks ago and it was fine. I have done a 20% water change this morning but he is still doing it this evening. Also I notice that he doesn't lie flat on the gravel but seems to be coming down to graze on it at a slight angle. Perhaps it is a problem with him not the water. Ph is 7 and amonia 0.
still worried
DD