I have 3 hoplo catfish in my 200L tank. When ever they are going to breath they are hitting the glass lid on the top, How low would I have to drop the water level so they don't hit it and risk hurting them selves?

Ps. they already have a 2 cm gap.

Mine never hit the lid and when the water is at its highest, there is a 4cm gap between water surface and lid.

Are they really likely to hurt themselves?

Mine have never moved that fast. They just mosey on up to the surface then drop down again.

they usually just do that, but the last couple of nights i have been hearing them hit the lid, and i know they can jump high if needed as one jumped out when my lid was off for a water change last weekend

i wonder if its the gut breathing that cories do? if if it is perhaps increasing the water agitation may mean they do it less

i wonder if its the gut breathing that cories do? if if it is perhaps increasing the water agitation may mean they do it less

It is the same gut breathing, and no matter how aerated the water is i doubt they would stop it completely, as it is natural for them, i just want to make sure that they font hurt them selves when they do it, in there hitting the lid.

They are bubble nesters. Possibly they are attempting to spawn?