im new here and have been getting alot of help with my 40 gal fish tank setup. i have a newly finished cycled tank with fish in there (4 rummy nose tetra, 2 oct catfish, 1 spotted puffer) i was wondering if changing out my tacky pink gravel with aquarium sand would mess up my cycled tank since i read alot of bacteria are in the gravel. also what should i do with all the fish in there when i do change the gravel?