While fish make amazing pets, they aren’t exactly known for their interactive nature. Sure, they may look attractive in a perfectly aquascaped aquarium, but for the most part, they rarely do more than swim around peacefully and maybe peck at the occasional spec of algae.
But all that changes at mealtime for the fish. They become more shameless than a hungry puppy, begging at the front of the glass, zipping around the aquarium, and basically doing anything to get your attention.
And this is the reason that many fishkeepers overfeed their fish. It’s really the only time they get to interact with their prized pet, and it can be addictive, watching them dance for you as you prepare their food.
Many fishkeepers eventually start to add an extra feeding here and there, enjoying the new-found interaction with their fish. But like many people, you’re probably thinking, what could be the harm of giving them a bit more food?
Unfortunately, the truth is that if you’re overfeeding your fish, you’re probably doing a lot of harm. The dangers of overfeeding go far beyond just ending up with an overweight fish. When you overfeed a fish, you’re putting its life at risk. And no responsible fishkeeper wants to do that.
How Much Should You Feed Your Fish?
Every fish is different and there’s no precise answer on how much to feed a fish. But if you know their diet, then it’s relatively easy to estimate how much they need to eat.
Most fish available in the hobby are omnivores, meaning they eat both plant and animal matter. These fish should only be fed once daily and all the food should be consumed within 3-4 minutes. If all the food isn’t gone after five minutes, then you’re probably overfeeding your fish.
Sometimes, fish still seem to be hungry after the five minutes have elapsed. But that’s because most fish are opportunistic eaters. In the wild, food is often scarce and a fish will eat as much as they can catch or scavenge. The fish knows it may be hours or days until their next meal, so if they want to survive, they need to eat every chance they get.
It’s this behavior that causes problems in the aquarium. The fish quickly learns how to beg for food and to the inexperienced fishkeeper, it seems like they’re hungry and need to be fed more often. This is a vicious cycle, with the fish always fearing a scarce time, and the fishkeeper constantly feeding the fish because it seems hungry.
But don’t worry – even if you’ve been giving your fish multiple feedings a day – it will still adapt to the new feeding routine. Even the hungriest omnivore fish will be fine with being fed once a day and they’ll thank you for it later.
When it comes to herbivore fish, feeding is a little bit different. These fish constantly graze in the wild, eating algae and plant matter. The once a day feeding regime simply won’t work as well for them. For these fish, they should be fed twice daily, with regular feedings of blanched vegetables to graze on throughout the day. But make sure to remove any uneaten vegetables after 24 hours, or they will start to foul the water. (If you want more information on feeding vegetables to fish, read How To Feed Vegetables to Fish).
Dangers of Overfeeding Fish
Overfeeding your fish can result in sick fish, algae blooms, mass die-offs, clogged filters, and dogs and cats living together (alright, maybe the last one isn’t true). But there’s no question – overfeeding your fish will give you an ugly aquarium, with sick fish, and thick mats of algae.
The first problem with overfeeding a fish, is that they often don’t eat all the offered food. The uneaten food will then settle to the bottom and start to decay. Even in a mature, fully cycled aquarium, this will often foul the water, causing a dangerous buildup of ammonia and nitrites. (Don’t know what a cycled aquarium means? Find out here.) These chemicals can injure a fish, and are why overfeeding is probably one of the biggest causes of fish loss in the hobby.
The second problem is that increased feedings, unsurprisingly, result in increased waste production from a fish. This is especially pronounced in aquariums with widebody fish like goldfish, whose only purpose in life seems to be eating and pooping. The waste and its by-products can foul the aquarium, and will often result in algae blooms – which while harmless – are extremely unattractive.
And lastly, overfeeding can directly affect the health of a fish. While rare in most species, overfeeding can result in a fish developing a fatty liver. The one species of fish that seems to suffer from this the most are bettas. This is probably because most bettas don’t have much space to move around in their aquariums, which means overfeeding is combined with lack of exercise. But it can affect any species of fish, so it’s important not to overfeed any fish.
It’s relatively easy to correct bad feeding habits, and by properly feeding your fish, you’ll reap dividends for years through healthier fish, more attractive aquariums, and better functioning filters. So, no matter how much your fish beg, make sure you don’t overfeed them.