Hey everyone! How you guys been, I haven’t been on in a wild, and then I couldn’t remember my old password and what email I had it on so I just made a new account. Anyway, I’ve had my 20 gallon tank for around 3 years now, and I’ve kept my danios for the whole time, might sound like a boring tank but I just tried to use it to grow a load of plants. Anyway recently 7 of my 15 danios have been slowly passing on. I don’t 100% know what is causing this but I think my fish r just simply reaching the end of there life span. Anyway I have another tank I can move the rest of them into to enjoy the rest of there lives and I’m just wondering what you guys think I should put in the soon to be empty 20 gallon tank. It’s a 20 gallon high tank, not a long 20 gallon. Now recently I’ve been kind of interested in maybe trying my luck at salt water and have a small coral tank with a few fish, but I’m not sure if it’s just possible to drain the water and then just add salt water in and using the current lights and filter. Is it possible to just make that switch by adding salt water and live rock and sand?