[Bug] Fish in Advanced Aquariums not moving/stacked in one spot

I'm not sure if it is just certain types of fish (maybe due to size?) but the fish do not seem to move around like others, and as well fish like Ember Gar, and Ember Wrasse after about 4, the rest all stack on one spot, none move at all.

I'm not sure if it is just because of the number of tanks or what, but I only have 6 tanks currently running, two are empty now and still issues with fish not moving from the spot they spawn in when added to tank.

Also can we please have the fish regenerate at half of the decomposing rate. This way when in water they regenerate slowly if it is powered/water supplied, but if they are not they will still die eventually. This would fix some of the issues I have read with loading, and as well if you are moving fish around/health lost while fishing etc.