Hi! I have a 15 gallon tank with a female platy, female Dalmatian molly, and 4 rummy nose tetras. The platy has been in the tank for a year now and is used to our current lighting schedule (aquarium lights on for 12 hours). The molly and rummy nose tetras were added to the tank a week ago. It doesn’t seem like they’ve adapted to the light yet. When the light is on they swim rapidly against the front of the glass back and forth repeatedly. The molly looks erratic at times with the circles she does. But when the lights are off they explore the tank, swim through the plants, are calmer in nature etc. The store we got them at was extremely dark. I’m worried the light is really stressing them out, especially the molly. But also don’t want to mess with the platy’s routine too much. Any tips? Thanks!
12 hours is a really long time to have the lights on for. Mine get natural daylight until 12noon then the timers kick on tank lights, then at 7pm it kicks them off. In the summer its still light until 930 here, so they still have SOME light until it gets dark. Maybe they arent liking the length, or maybe theyre brighter than used to (especially if the shop was dark). Maybe there isnt enough hiding spots for them, etc. Id try shortening the light period for sure and go from there.
I agree if they seem to be stressed I'd reduce the time that the lights are on. You can also add a filter of sorts to dim the light down a bit while they adjust. In the past I've used everything from an old t-shirt turned rag usually light colored to paper from my son's old homework to filter down the lighting for new fish. Especially in brightly lit tanks some fish have a bit of an adjustment as most stores don't spend much on lighting their tanks.
