Hi Sarah!

The ulcers you describe were most likely caused by an organism called Aeromonas aeruginosa, a bacteria that is always found in pond environments. It is one of the "housekeeping" bacteria that, in a healthy pond, help break down the mucus present in fish excreta and sloughed slime coat.

It becomes a problem in ponds with poor water quality, overcrowding, and parasite problems. The stressed fish lose the ability to defend themselves against normally well-tolerated stresses and develop ulcers. The ulcers disrupt the fish's ability to regulate their fluid and electrolye balance and the combination of the underlying stress, infection and fluid imbalance ultimately kills them.

Your survivor is probably okay at this point, but I'd wait to off-load it until late spring. If it survives the very stressful transition into warmer weather without problems, it is reasonably safe to give away, as long as the ponder you are sending it to is willing to isolate it for several weeks to safeguard the health of his pond.

Bob