ah! you have fbt's! that makes live a bit easier, believe it or not. what's their water temp? if the air in their tank gets warm for them, they'll go in the water to cool off. keep the water in check and i believe you should be good. but i do admit, i never kept fbt's. but the summer months were why i always built paladariums for my white's, so they had water to cool down and soak in.
i'm sure they have a cold limit, much as everything does, but i have no idea what it would be. a guess though, would be mid 60's since their natural habitat is fed by cold, mountainous streams. not that the water they live in is cold, but i think you get what i mean.
