Weight Management in Fishes

Unlike other pets like dogs and cats, fishes can’t communicate if they are hungry or if they are overfed. It’s difficult for owners to gauge how often and how much food to feed their pet fish. Like other vertebrates, they store energy as fat within their bodies.  If they eat less, they will burn fat for energy, and lose weight and if overfed, they will gain weight.  Hence, it is important to understand weight management practices for fishes as like other pets. 

Firstly, let’s break this down into how fishes eat. When in an ocean or sea, a fish would eat on every opportunity it gets. However, if you keep them in an aquarium, they will have to be trained to eat on a fixed routine else they might jump onto food every time you feed them.  Ideally, the feeding should be done 2 times a day but if you have growing fishes, it can be done 3-4 times a day. Some herbivores like Silver Dollars, Mollies, and Farowellas need to eat more frequently because of their small stomachs. If you have a nocturnal fish like a catfish, you might need to feed it during the night It would probably be better for your fish’s health if you fed it less for a while, rather than not feeding it at all.

Weight Management in Fishes

The common causes of a fish being Overweight are as mentioned below:

  1. Carrying Eggs: Female fishes might look overly fat because of being pregnant. Observe the areas near the abdomen. If there seems to be a lump below the abdomen for 20-40 days, then there is a high possibility that she is carrying eggs.  Females may also have a sort of stain or spot on the abdomen that is shiny black or red, indicating that they are pregnant. For her to release her eggs, there needs to be a male fish present, and good water with the right temperature. This varies species to species. If the fish remains egg-bound, she could become sick and infected. Consult your vet for facilitating the process.
  2. Sickness: The majority of fishes in freshwater aquarium get diseased of Dropsy, which is a condition that makes your fish become much larger than her size and is often accompanied by protruding scales, making your fish look like a pinecone. This disease is usually fatal and communicable. Hence, you might want to quarantine your fish and consult a vet for providing possible medications that could give fish another chance of survival. Kidney diseases can also make your fish look large, one needs to consult a vet whenever any abnormality is observed
  3. Tumors: A tumor may be another cause of your fish looking larger or fat. Tumors will usually be uneven and are typically benign. Even if they are cancerous, there are rarely any treatments for fish.
  4. Overfeeding: A wrong diet or portion size can also cause your fish constipation and digestive issues because of which it may gain weight. Overfeeding can also have more serious consequences than digestive ones. More food means more waste, and overfeeding increases levels of ammonia and decreases levels of oxygen in the water. If you see your fish gasping at the surface of the water, this means that the water quality is poor and you may want to try reducing the amount of food they are being given.

Most overweight fishes have higher chances of developing Fatty Liver Disease or Liver degeneration. Be certain that your fish has reached its full adult size before assuming that it is overweight.  You may want to consult a veterinarian to evaluate your fish’s physical condition before reducing its food intake.

Although, a very less number of fishes become underweight due to an inadequate diet or an underlying disease, it is important to understand the reason and consult with your vet for a proper diet management plan. Underweight fishes have higher chances of contracting a fatal disease called Skinny Fish disease.

Dealing with underweight or overweight fishes:

The first step to keep your fishes healthy is to understand their diet and nutrition needs, which can be done by consulting your vet. The next step is to monitor and control the dietary and behavioral aspects of fishes regularly and see for any abnormality. This can be summarised as follows:

  1. Feed on a schedule– Keep it twice a day and if possible, keep more frequent and smaller feedings
  2. Feed the proper food and in a proper amount- Feeding an improper, poor quality food will not only lead to malnutrition, it will lead to more waste since the fish will not eat it. Choose the appropriate form (e.g. flake or pellet) and the appropriate size based on the tank or pond inhabitants. Some fish will need floating food, while others prefer food that sinks. Research the feeding habits of your fish and feed accordingly. The best way to determine how much to feed your fish is to observe them at periodic intervals while they feed. Add a small amount of food at a time. If all the food is eaten within several minutes, feed a small amount more. The general rule is to only feed them as much as they can eat within 4-5 minutes.
  3. Remove uneaten food– Remove uneaten food with a fine net, these uneaten food decay in the pond and causes an offensive smell and creates an unsafe environment for fishes.