My Fiance screwed over a tiger cichlid!!

Our son won 2 goldfish from a local fair and for some reason within 2 days the fish were dead? she went out and let the kids pick which fish they wanted and they chose a tiger cichlid...SMH!!! its in a 10 gallon tank and i know from just 1 week of dirty water that its tooooooo small for him and he seems depressed compared to the tigers at the LFS...so if anyone is interested in adopting him/her for free then id be willing to pay half of shipping and other costs just to see him go to a better home!! thanks and please let me know if there is anything i can do!!

that was my next question was how to take care of him until he finds a new home...i just changed 100% of his water and he seemed more stressed than just having a dirty tank...so please explain how to keep it under as little stress as possible while changing water... my rookie equipment is

siphon gravel vacuum.. a net ..2 different scrubbers for tank walls..stress coat and a fish bowl... help please..i feel really bad for him or her!!

i dont think its an oscar... and i went today to return him but they have a 14 day return policy so no go...i can do a 50 % change daily..do i need to get him out of the tank to do so or just remove 50% and add while he is still there???

awesome...im going to look into "cycling" so im guessing i didnt...poor guy...in this case ignorance is not bliss

just did..and funny cuz i just checked the 2 day old 5g glo fish tank and its cloudy...i know to test for ammonia..nitrites and nitrates but im still not too sure what to do when one is out of whack??