Fish and diet?

Basic questions:

- What are you feeding them, how often, how much?

- What fish lives in which tank? We need numbers and exact species.

- Filter type, temperature, water changing schedule for both setups, and ammonia, nitrite, nitrate readings if you know them (pH, hardness if you know them, though if all of your fish are getting thin, it might not be the problem)

- Describe the decorations please or add a photo.

- Anything weird about your fish? I mean: behavior, color, feces...?

- - - - -

Based on your description it's safe to assume that something is off with your fish. Many fish in the stores are skinny to begin with so losing weight is not a good thing. Also what stores sell are mostly baby fish, so proper nutrition is very important so they can grow into healthy adults.

What we are trying to rule out range from trivial things like you giving your fish too little food, bad quality food the wrong type of food, as well as some serious stuff like internal parasites or bacterial infection. Some fish refuse to eat when they are stressed, so we are also trying to rule these out by looking at the water parameters, numbers of fish and the decoration.

In general, you have two types of fish:

- micropredators: the danios and the tetras

- omnivores: the platies and the mollies.

Both species can get frozen and live insects (bloodworms, brine shrimp, blackworms, daphnia etc.) and the omnivores should also have vegetable matter in their diet (cooked peas, zucchini etc. blanched leafy greens like spinach, romaine lettuce etc) - though some danios, tetras will nip at the veggies too.