When you add new fish to an established tank, it is always wise to quarantine first!
Also can you say for certain what your neighbors water parameters were? Maybe there was already a high ammonia level and adding 1 more large Pleco took it over the edge.
I do have to admit that I stopped by the store recently and many of there fish were in bad shape with what appeared to be fin rot and fungus. The funny thing is I also visited a few other LFS and found very unhealthy fish in many of them. I have not found very many places without issues.
Also can you say for certain what your neighbors water parameters were? Maybe there was already a high ammonia level and adding 1 more large Pleco took it over the edge.
I do have to admit that I stopped by the store recently and many of there fish were in bad shape with what appeared to be fin rot and fungus. The funny thing is I also visited a few other LFS and found very unhealthy fish in many of them. I have not found very many places without issues.