sick tank

[micheline905]

Hello. Am experiencing some sad times w/ my 29 gallon tank. Came on rather suddenly. Have lost two black tetras and one serpae tetra. Heater is turned up as high as it will go, but thermometer is only about 72 degrees F. Fish will NOT eat anything. :sad am going to try another 1/4 water change and see if this remedies the problem. Also have some live plants: Amazon swords

[HarmonyAZ]

I am a newbie too but wonder if your heater is working? Is there any other explanation for the tank being at 72 (assuming the heater is not)? I hope someone knowledgeable comes along...
:(

[DEmigh]

HarmonyAZ raises an excellent point. Is the temp reading reliable?

Also, can you get test readings for ammonia and nitrite?

Are the fish showing other signs of stress (clamped fins, panicky swimming)?

Since they're not eating at all, are you scooping out the leftover food?