Gourami With Swollen Eye / Neon Tetra With Purplish Tail

[nem2k2]

Hi guys,

I have a problem with a couple of my fish... one of my dwarf gouramis has a slightly swollen eye.. it's also a little redder. It's been like this for a week or so but it didn't look too serious.. I thought it might improve after a few water changes. Any ideas on what the problem there could be?

Also, I noticed one of my seven neon tetras has some discoloration in his tail - one side appears purplish in color, and the other is pale red. The tail also seems to be drooping a little bit... is this NTD? Would I be best euthanising or isolating him asap to prevent any of the other tetras from getting sick?

Any advice would be greatly appreciated. I will do some daily 25% water changes in the meantime.

PS: I will try and post some pics when my camera has recharged

EDIT: whoops, forgot the important stuff..
I change 25% of the water every 2 weeks
No chemicals/treatment added
40L tank, has 7 neon tetras, 2 dwarf gouramis and a 1-inch pleco (yes I know the pleco will grow, I plan on getting a bigger tank when I have the money and when he gets too much bigger)
Bought 2 clown loaches today, I only noticed the tetra's symptoms when I was adding the loaches.

 

[WILDER]

Your well overstocked for a 40litre tank,with out the clown loaches i would see if the lfs will take then back the clown loaches, as the need a 90gal tank, you need to preform the 25% water change once a week,can you post water stats as i don't like the sound of the neon tetra's, it could be stress for now due to poor water quality, ammonia,nitrite,nitrate,and ph.