I have a 48.2 gallon and all my fish keep dying. I had 1 tiger barb, 1 fire barb, 1 black skirt tetra, 5 guppies, 1 female betta, 1 hatchet fish, 1 red minor tetra and a cory cat in a ten gallon. my bettakilled 3 guppies i moved the betta into a 2 gallon then the other 2,got 3 new friends that were females this time. The 2 were injured and they died. my female guppies all died within 3 days(not from betta) I worried and instead of using my 48.2 for a turtle i decided on making it a community tank and move my goldfish to the 10. the tank was alredy cycled so i put some fish in. I bought a denison barb and 8 neon tetras. i moved my black ghost knife into that tank because of nitrates, he had a nitrate burn. after a day 1 neon died. then the ext day another died i got suspicious that my ghost knife was killing them. I moved my 6 remainning neons to a 5 gallon and none died. sfter my ghost knife healed a week later i moved him back 2 his tank. Then i put my neons back in the 48.2.after a few days i decided since my 55 gallon cant keep nitrates down that i would move my 3 dwarf gouramis and 2 bolivian rams to the 48.2. after 2 days i pu in all the fish that were currently in my ten.*GOLDFISH* goldfish were now in my ten. After a week i added 4 more tiger barbs and 4 more red minor tetras. then all my red minor tetras and my tiger barbsfins were ripped. another neon died. i left the ripped fins alone for 3 days then i realized now my dwarf gouramis haave ripped fins. i had 2 go to school so i came back and 2 died. i immedietly moved the dwarf gourami 2 the bowl and moved the betta to a .5 gallon. I give away 5 tiger barbs 2 my frien and now there fins arent ripped and theyre all healthy. He also gave me a cory cat.i boy 4 ottos pr my 10 gallonay 2 die the next day 2 die and right now one just died. 2 died from 48.2 gallon 3 died from the 10. I just thought that it was going to happen after what i saw in the store. 3 of them were dead at the store then he got one living and we turned around and it died. i set up a 12 gallon and i just put the dwarf gourami in and i realize that all my fish left [/FONT]in my 48.2 i (only 4 neonx the fifth one i havent seen in a while) have ripped fins except 4 1 fire barb, 1 denison barb and 2 bolivian rams. i move my black sjirt tetra with is my oldest fish to my 12 gallon. this is the present no more fish have died. PLEASE HELP!!!!!!!!!!!