What about swim patterns. I hear certain ones mean something. Like swimming up and down in one spot, or cruising the glass. Does that mean anything
Usually signs of stress but depends what you or others are doing,like if you standing close to the tank,fish could think it going get fed so getting excited and letting you know it wants food,( fish will eat and eat and eat so dont overfeed and watch your nutrient export system)
But as said above all depends on how your fish usually is,we get used to our fish as we get to know them.
If the water is bad they swim erractically like fish in a uncycled system with amnonia still in the water,usually it is best to keep tank stable and make changes slowly but if fishes health/ life at risk then sometimes we need to act fast and make fast changes ( like if amnonia in tank then we do large water change to dilute the amnonia)
Fish could be pacing up and down glass as it a algae eater and trying to eat algae from glass or could be agressive fish in tank and it trying to escape and just swimming erratically.
So aslong as we cycle tank, aclimintise all new arrivals,
Do our stocking list wisely,and test water regulary ,appropiate tank size ,add fish stock slowly rather than say 10 fish at once,and give our fishy friends best surroundings we can and if something goes wrong then do the appropriate measures to rectify the problem.
Also one more thing to look out for is fish losing colour as a unhealthy or stressed fish generally loses colour .could just be stress or could be indication of dieseses or parasites but research each fish you want before you get it as some fish prone more than others to certain dieseses like brookenella ( which was once called clownfish diesese )
Also swim bladder problems where fish cant get its balance swimming,but again maybe it a hippo tang and alot say these act very strange often in their swimming/hiding in rocks behaviour .
