Sunken eyes and sick looking Gourami  - 04/14/07
Hi, thanks for your help. I've had fish for five months now and I love the hobby! In my 55g tank I have: 3 black skirt tetras 3 dwarf gouramis 6 neon tetras 2 dwarf platies 2 angels (1 small, 1 medium) 1 guppy 1 Australian rainbow 1 small Pleco Within the last week, I've lost my 2 dwarf platies, a Gourami, and now another Gourami has big problems.  My platies were dead within 15 hours of feeding frozen brine shrimp.  This was the first time I've used this and I know I overfed!
<Fish don't die from being given too much food. They die from too much food being put in the aquarium, and the food decaying and producing more ammonia than the filter can deal with. The ammonia poisons the fish.>
My Gourami was lost a few days later after a night of the power fluctuating on and off for a few hours.  Today I noticed another Gourami seems to be very lethargic (resting against leaves and lying completely motionless).  His eyes are dark and appear to be sunken a little and the ends of his fins are brownish.  
<Dwarf gouramis are incredibly prone to "mysterious" deaths that appear to be caused either by bacteria or, some recent research suggests, by viruses. Basically *all* commercially bred dwarf gouramis have a high probability of being infected. My advice is don't buy them. Opt for the similar (and apparently unaffected) species such as thick-lipped and banded gouramis, Colisa labiosus and Colisa fasciata.>
I'm beginning to wonder if my previous losses are related to my current problems with the Gourami.
<Can't think why.>
The last few weeks, my water has tested "perfect", no ammonia, ph averages between 7.0 and 7.4.  I did a 10% change 2 days ago. Had water tested today with no ammonia, ph of 7.2, a little nitrates? (can't remember if he said nitrates or nitrites, he said it's what eats ammonia).  He didn't give me a number, but suggested it's "a little" high and suggested a water change.
<Nitrates are not especially dangerous, but nitrites are very dangerous, so you do need to clarify this! You want zero nitrites, but nitrates are basically safe anywhere up to 50 mg/l if not more. Yes, zero nitrates are best, but with standard freshwater fish even the fairly high levels of nitrates in municipal water supplies aren't really a serious problem. Anyway, you shouldn't be relying on the guy in the store to test your water and provide advice. It is FAR better to have your own test kits. If you're cheap (like me) buy the dip-strip ones, and slice 'em along the middle to make two from every one strip. Some brands include pH, hardness, nitrite, and nitrate all on one strip -- very useful. You can then compare your results with what you've learned from your favourite aquarium magazines, books, or web sites.>
When I got home, I changed 20%, and now, several hours later, my Gourami seems to be on the verge of death!
<The dwarf Gourami is going to die anyway. At best, you can move it to a quarantine tank. Because the problem may be viral, even antibiotics aren't much help (antibiotics don't do anything to viruses).>
I typed in "sunken eyes" with "Gourami" and couldn't find any answer.  Does this sound a water issue, or maybe a disease or sickness of some kind?
<If it's just the gouramis getting sick, there's not much you can do beyond optimizing water conditions and quality, providing the best diet possible, and hoping for the best.>
All my other fish appear to be healthy, including my neon tetras and both angels.  
<You do realize angelfish eat Neons, don't you?>
One more thing...to try and give you a complete picture...about1.5 months ago, I used some water and all my decorations to quickly start my new 55g tank. (water tested normal in about 1 week) and I've added about 3-5 fish/week.   I am no longer  using my 29g tank.  
<OK.>
Thanks for your response.  I tried to find an answer in the forum, but it said it was temporarily unavailable.  
<Cheers, Neale>