My flaming tetras are dying one by one

Question
29 gl. tank - 2 skirt tails - blue spotted gurami - austrailian rainbow - rainbow shark - 2 glass fish - african dwarf frog - and a pleco.  no ammonia, no nitrites, ph is 7.4 we have had our tank for three years. All of our other fish are fine but the flaming tetras are starting to bloat and die.  Only the tetras.  Can you help?

Answer
Hi,
Well this is certainly odd. Usually poor water quality is the source of fish deaths, but since you have no ammonia or nitrite, that is nearly ruled out. You should buy a nitrate test kit as well though, just in case that is the cause of the problem. It should be under 20ppm. Thankfully, it is fairly easy to get downs; live plants will help lower it. The pH is slightly high for the Tetras, but since you've had your tank 3 years, they will have most probably grown accustomed to the slightly more alkaline water.
Do 20 percent daily water changes for a couple of weeks, and feed them a few shelled and boiled peas every week. Peas help their digestive system if they are constipated, which is highly likely.
When no more Tetras have died, remember to buy some more to raise the numbers to 6 or 7, but don't buy more until there has been no deaths in a few weeks.
I hope no more die.
Good luck,
Kathryn