Seahorse with Swollen Tail

Hello,

A few weeks ago I noticed my one male seahorse had a bump on its tail, not really anything that concerned me at the time.  It looked like a swollen wart.  It didn’t seem to impact his appetite or his swimming ability.  Recently, I went away on holiday and came back and now the bottom 1″ of my seahorses tail is quite swollen.  Problably about 3-4 times the size it should be.  It does appear to hurt him a bit as I had my hand on his tail yesterday trying to see if there was any wounds or skin abrasions and he did not like me touching it at all.  Whats worse, is my 2nd male that I have in the tank now also has the same “small wart looking” bumps on his tail.   The 1st seahorse has pretty much went off of food, the 2nd is still eating aggressively.  GBD or tail bubbles do you think?   I should note that there is nothing wrong with the flesh on the tail — it is as you would expect it to look, just swollen.  There is no wounds and no marks whatsoever.  There is no heater in the tank and nothing in the tank that can sting the horses.   

I’m in the process of obtaining Diamox just in case it is tail bubbles.  Someone please help if you are able, I really don’t want to lose these guys. 

Water parameters in the tank are excellent.  Temp of tank is between 72-73, Salinity at 1.024.  I feed twice per day with PE Mysis and I have 4 CB Erectus in this tank — 2 males and 2 females.

Thanks,

Matt