Hello -

One of my tanks is a planted 26gal bowfront with a school of danio tinwini, or gold ring danios, sometimes known as fire ring danios. I started with a school of 11, added 10 more, and for a while they did well. Now they seem to be failing - their school is down to about 10 again, and one by one they are getting really skinny and then fading away.

Their tank mates are one honey gourami, one red arc pencilfish, one siamese algae eater, and 12 kuhlii loaches. (There are also two baby swordtails in there, less than 1/2 inch, that were born in another tank and are just growing up in the 26). All the other fish are thriving and doing great, full colors, no aggression seen. The danios aren't hiding, they are usually out in the front and active and they seem to eat well. Oh and there's a UV sterilizer in that tank also.

The plants are doing fine, I do a 50% water change every 1-2 weeks. Water parameters with API liquid test kit are: pH=6.6, ammonia=0, nitrites=0, nitrates=0. I keep a little crushed coral in the filter cuz that tank likes to run a little low on pH, so I just added a little more last weekend. I feed them a mixture of flakes, bloodworms, brine shrimp, and sometimes tubifex worms or the veggie mix that comes in the frozen food variety pack.

Any thoughts on what is going on? Maybe an intestinal parasite? My other two tanks are doing great - happy active colorful fish with no evidence of disease.

Thanks everyone - I really value the advice I get here.