Ok guys, here's the deal...about 2 weeks ago, i purchased a red tailed catfish.. he has a 15 gal. tank....he had gill curl one side, he didn't eat, and wasn't very active..now, he still has gill curl, already started eating but stopped 2 days ago and hasn't eaten again, and started hiding in a jar that i placed but doesn't come out even at night and there are no lights..I asked for help in my last thread and so far these are the things i have done,...I change about 10% of my water once a week, i siphon any feces that i see, and i've added a water plant to help cycle the tank,..the water in the tank is clean and clear although i don't know my water params because i don't have a water test kit..I doubt i will obtain one cause my dad won't buy one..it costs 900php(20$)..which might not seem much to you guys but very pricey for my dad i guess...everyone please help in answering my questions...will the aquatic plant help cycle the tank?? is ok to not own a test kit as long as i keep the water clean and change water frequently??how frequent may i ask will be ideal??i saw some water treating solutions and whatnot for sale at the pet store, do these help cycle the tank??and also advice, opinions, and criticism are all encouraged..many thanks everyone!!!!!