I'm after some advice, on sunday afternoon I came to the tank and my channa lucius had gone really dark and was laying on his side at the bottom of the tank, half an hour before hand he had been swimming around like normal looking the same as usual, so I don't know what could have struck so suddenly. I moved him over to another tank and he's been completely immobile since then. the only theory I have is that he's jumped and hit the glass lid and given himself brain damage, not sure what else could strike so suddenly with no other warning signs.

