oscar with big belly

Question
QUESTION: Hi Ron! We have a pair of tiger oscars. They have been together for 2 years. One is 8 inches long, one is 6 inches long. The smaller of the two stopped eating 2 weeks ago. They are fed daily but not in large amounts. We noticed that the belly on the smaller one is swollen and they are showing behaviors of mating such as lip locking and tail shaking. They have been going after the large plecko that is in the tank (which we have since moved into another tank). We just did another water change and added epsom salt as directed by a web site during our research. (We were thinking constipation). After reading more we are thinking maybe she is going to lay eggs. There is a small white round thing sticking out from her underside that has been there for two days. Any help would be appreciated. Thank you very much!
Debbie and Mike

ANSWER: Hi Debbie,
 That small round thing is her ovipositor (egg laying tube) and it strongly indicates that she is going to lay eggs (if she hasn't already).   

-- Ron C.
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>


---------- FOLLOW-UP ----------

QUESTION: Hi Ron and thank you for your answer. She did lay some of her eggs. Now for the past 2 days her belly is so big that she is floating on the top of the tank. She is breathing easy, but we feel bad watching her. Her mate has been very "supportive" and not picking at her. We did a water change, added Epsom salt as recommended and I believe there is not much else we can do. Thank you for any help!

Answer
Hi Debbie,
 Hmmm... that is very unusual.  I often hear about sick fish (ones that float). And, I hear about fish full of eggs that lay eggs.  But I have never heard about a fish laying eggs and then floating...  sadly I'm not sure that there is much you can do about this.

-- Ron C.  
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>