We have a 25 gal (tall) planted tank with cardinal tetras (5), german blue ram pair, rasboras (6) and some pepper. It's been a while since we added new fish and some old ones (tetras) have died. My wife wants like them black mollies... I am just worried about their well being in fresh water as they are brackish water fish. I heard they can be adapted,but I'd like my fish to be well rather than survive..... Any thoughts? TIA