The temperature is one of the things that can make your tetras sick. If a shoal is in an environment that is too cold or too hot, it will cause problems for their health. You are better off keeping the freshwater between 22 and 25 degrees Celsius. Characin will be happier and thrive when the aquarium resembles the tropics.
Keeping only one or two of these fish is not a good idea. For one thing, they are small and while their colors are bright, you will only get the full impact of this when several are swimming together. You should also add a few plants to the water so that they block out some of the light. The shoal will prefer filtered light.
They will eat any of the following:
- Pond Floating Fish Sticks
- Pond Koi Vibrance Fish Food
- TetraMin Tropical Flakes
- Tetra Color Tropical Granules