Red tailed shark - poorly or pregnant ?

Question
I have a 5-6" red tailed shark who is approx 4yrs old. Over the past couple of days he has been hiding in his cave more than usual, his breathing is laboured and his belly is huge but also a little pale. He is now near the top of the tank almost gasping for air? I have another red tailed shark, so wasn't sure if he was pregnant or on his last legs ??? All the other fish seem ok ?

Answer
Hi Jamie
Hmmm, he's pregnant?  Sorry couldn't resist :)  

I have one of these guys, they are a beauty!  One thing I learned a long time ago with them, watch their colors.  When the red tail starts to pale, and their deep black bodies start looking washed out, they're stressed.  Here's a good link with some info on them, has a section for breeding, need to copy/paste:

http://www.badmanstropicalfish.com/profiles/profile10.html

Now, it says it's pretty rare for them to breed in the aquarium, though possible.  I'm guessing it's probably sick, could be old age, not sure on their life spans.  Do you have a test kit to test the water parameters?  If not, should get one.  Ammonia and nitrite should read 0 ppm, and nitrates under 20 ppm.  Gasping at the top is a classic sign of either a parasite infection or ammonia or nitrite poisoning.  The hiding and breathing is all symptoms as well.  The swelling sounds like it may be dropsy.  Try doing an immediate water change. If you can, separate the fish into a quarantine/hospital tank.  Is it eating?  If so, you could try feeding it an antibiotic food, pet store sells it.  Other then that, just keep an eye on it as well as the others in the tank.  If it is a dropsy infection, it most likely won't make it.  Dropsy isn't contagious though, so that's good.

Let me know if you have more questions and good luck with him/her!!

Christy