My son has a 10gallon tank that we are learning this wonderful hobby from. Among the occupants are 2 ottos. These things tend to go nuts in the early evening.... They are at 1000% energy output - chasing each other, all over the glass, etc. Never see this behavior during the normal day, nor later at night after lights have been out for awhile. Just wondering if I have a couple of juvie delinquents here, or if the species in general is fairly active at this time of day for others.