Hello!! I'm not too familiar with this subreddit (and reddit as a whole) but was hoping I could get some advice on one of my albino rainbow sharks. For some reason, she seems to have a habit of going to the same corner of the tank and just... standing there. Literally. Sometimes she's facing the sky (kinda like she really is standing lol) but she's mostly just vertical and upside down (like in the 2nd pic), and kinda just chillin there. She doesn't spend all her time in her corner and is otherwise a perfectly normal shark, but she stands there often enough for me to notice (and worry).

At first I thought she might've had a swim bladder issue or an injury somewhere, but the moment I went to check, she just swam off and went back to normal rainbow shark behaviour. She eats well, moves around and interacts with the other sharks on the daily. 

She lives in a community tank consisting of 3 other sharks (1 other albino and 2 smaller, normal rainbow shakrs. All 4 of em were from the same tank when my dad bought em), about 7 medakas, 5 kuhli loaches, 2 hillstream loaches, 4 corydoras, a betta and some tiny pond snails. The tank is 90x23x15 (31 litres or 8 gallons) including wood, substrate & foliage. 

All the fish leave each other alone and nobody ever bullies or even bothers anyone else. The other sharks also have their own spaces in the tank, so I doubt her behaviour is a result of stress over her territory. Does anybody know why she has this habit? Is it a neurological thing? Is she unwell in any way? Does she just enjoy standing like a people? Any help is greatly appreciated, thank you everyone!! :D

My Albino Rainbow Shark is... vertical..?