I had over 140 Yumas in my frag set up, when someone gave me a yuma, from their system. unknown to me they had a wipe out of their yumas and gave me their last one. As a result, their one yuma melted within a week of having it, then in about 4 weeks i lost all but two yumas. they all bleached , or melted to a goo, and these are rics that were healed, and had been sitting in the one spot for up to 6 months. The tank was a 440L trough, about 6 ft long. The rics were spread out, and they didnt need to have contact with a melting ric to start melting themselves.
luckily i kept a few of each colour in my main tank!!!!!!