Hi, I am deciding on a substrate for my baby FRT, was wondering if coral sand is a good choice? Also should I use a white or black substrate (white substrate is a little coarser than the black one). Any advice is appreciated, thank you.
In my experience, the best substrate for water turtles is no substitute if you are keeping them in something like an aquarium. Gravel and pebbles can be accidentally swallowed which will cause impaction. Sand is slightly better as it is finer, but swallow enough of it and impaction can still happen. Moreover, poop and leftover food can accumulate in the substrate and rot, which worsens water quality.
If you do insist on using substrate for your turtle, pick something that cannot be swallowed. In your case, sand is kinda risky and should really only be used for certain species of soft shells. Personally, I wouldn't risk using sand just to avoid any risk of accidental ingestion.
FRT need substrate! Since they are soft shelled they need substrate to completely submerge themselves under. This will help fungus growth become non existent. I use cichlid sand from PetSmart. Or use super super porous sand.