Well you could always get some Tetra's or Rasbora's. Not sure what you keep your temperature at. And yes that shark will eventually get a little to big for them. I've had yo-yo loaches with shrimp and they were just fine. A few little ones will get picked off but mine were fine. And I've got shrimp in most every tank I have including my ram tanks and from time to time they will eat one but for the most part the shrimp are fine and help keep the tank clean.