You listed cleaner fish but I think you mean cleaner shrimp? Right...Same thing happened to me....I bought a larger cleaner shrimp for my tank and it died...After a few weeks I bought another one a bit younger (smaller) and it did great since then I added another with great results....I really think with all the trouble you went thru acclimating and water quality, like myself having one die. I believe you bought an already stressed cleaner shrimp my advise would be buy another but ensure he is healthy. I do so by researching and knowing what to look for at the lfs
, I really look at the tank health at the lfs
I also test there water before I buy, I ensure fish, shrimp ect... are active and eat before I buy...ect.. the only true cleaner shrimp I know of is the scarlet skunk cleaner shrimp.