I have a small 35gallon planted community tank that has been established for just under 6 months. The problem is that although the rest of my fish appear to be fine I have now lost 3 blue neon dwarf gouramis over the period of a month. The strange thing is that I have 4 other dwarf gouramis ( honey and red ) that are fine. Its just the blue ones that keep dying.
If they had all come from the same source I might blame a bad batch but one of them was from a completely different store.
I thought this species was quite hardy. Can anyone shed some light on this mystery.

Here are some details on my tank that might help.

Other fish 3 guppies, 2 pearl danio, 2 dwarf red gourami, 2 dwarf honey gourami, 1 white tipped tetra, 6 cherry barbs.

My water is tested just before a 25% water change every week and is rock solid at PH 7.6, ammonia 0, nitrite 0 and nitrate 0 to 0.5

I have a nutrafin Co2 system running

Many Dwarf Gourami, colisa lalia, are currently carrying an iridovirus which is currently incurrable and kills them. Most in my area advise against buying them as the virus is now suspect to be mutating and affecting other fish. This could well be what you're seeing.

Unfortunately, most shop bought dwarf gouramis are no longer hardy at all. Have a read of the pinned topic on dwarf gouramis at the top of this section.