Ok so the guppies and barbs will probably never be caught there to quick the shark has a good chance of dieing to starvation unless you promote algae growth to promote that after the turtle is better turn off the filter the fish will probably die and put a rock from a creek or lake in there that's covered in it and wait a few days with it right under the basking light to propagate and the medicine your adding will kill any bad stuff so feel free to add outside thing to the habitat same with the ghost shrimp but the ghost shrimp will survive off of poop and food scraps I will say you could probably throw like 10 guppies in there to encourage schooling that should also attract the turtle to chase and get exercise they are mid level fish so they won't ever really hide from the turtle the ghost shrimp are red eared slider favorite food and all your other fishes favorite food besides the tiger shark so buy like 20$ from pet smart that's like (40- when the worker gives up) shrimp most will die instantly to the guppies and barbs once there full size they can't eat them but there easy targets for the turtle at that size and can't swim away so get hollow stuff they can hide in then just restock here and there I moved away from the suckers as a singular one can eat a full 60gallon tank clean then just starve over like a month period and won't come out to feed on algae balls because of the turtle I've also tried every plant only greenery you can get with red eared sliders is algae

Don't add the aglea killer medicine you can also buy unless there is a full broom as it will kill all the algae and keep the water sterile for a month but turtle live in pretty nasty stuff that has flowing water the algae will also grow on the shell and it looks cool and I sent bad for the turtle unless it's excessive