i was having a debate with a friend this weekend. i swear i seen my purple tang swim backwards, maybe just a short distance to get food. my friend who is also a hobbyist says tangs cant swim backwards. silly question but i am very curious
Yes they can move backwards for short bursts. Moving backwards though is not natural for many animals which is something to keep in mind if you're ever stranded out in the woods and need to trap food.
There's quite a few fish I can think of off the top of my head that move backwards.
If they can't go backward, they must be able to make a U turn, or they will be trapped very frequently. Many fishes can swim backward, just not very efficient at it.
My redlip, midas, canary and flametail blenny are all able to swim backwards. They pull up to their cave, then swim backwards until they're inside. Every eel I have ever owned was also able to do the same thing. Off the top of my head.
My yellow tang can swim upsidedown. I seen this happen a couple of nights ago. He was swimming through a cave and that is what he had to do to get out.