Can Oscar Fish Eat Guppies? Benefits & Risks

Yes, oscar fish can and will eat guppies and other smaller fish, consider that the Oscars can grow up to 12 inches in captivity. However, there are some risks feeding your oscar fish with feeder guppies bought from the store.

Oscars have some predatory blood running through their veins are and are rather aggressive and territorial and require a lot of space to remain comfortable in their habitat.

Needless to say, they aren’t quite fitting for community tanks, especially if you’re planning to pair them with small and shy fish species like guppies. Seeing how guppies can only grow up to 2.5 inches, it’s understandable why Oscars would hunt and eat them.

Pairing Oscars with larger fish won’t help either. While the former won’t be able to eat them, violence is almost always guaranteed due to Oscar’s predilection towards territoriality. This is the main reason why most aquarists prefer to keep Oscars alone in larger tanks, preferably 55-75 gallons. They won’t mind since Oscars don’t need social interactions to thrive.

But, coming back to the article’s main topic, we have already determined that Oscars will happily eat guppies or similar-sized fish whenever possible. But should they? Let’s see why it may not be such a good idea to feed guppies to your Oscar.

Is it Healthy For Oscar Fish to Eat Guppies?

It depends. I would advise against feeding your Oscar commercially-bought feeder guppies for one simple reason – you don’t know what you’re getting. Here are 3 of the most widespread issues related to commercial feeder guppies:

  • Unknown genetic makeup – This issue stands whether your guppy comes from commercial fish shops or independent breeders. You can never tell whether your guppy has genetic conditions or showcases a predisposition towards certain health problems. This can leave the guppy vulnerable to diseases that could pass on to your Oscar.
  • Improper conditions – Fish shops aren’t exactly famous for keeping their fish in pristine water conditions. In most cases, guppies will be overcrowded, overfed, and maintained in subpar environmental conditions, to say the least. This could lead to guppies experiencing bacterial and parasitic infections or diseases that won’t exactly fit the profile of a proper feeder guppy.
  • The use of growth hormones – This is a widespread problem in the guppy business, with people doing whatever is necessary to boost the guppies’ growth rate. This allows them to sell the guppies faster, sacrificing the fish’s health for profit. That’s because using growth hormones will force the guppies’ growth rate artificially, which will affect their immune system. As a result, you may get sick fish that show no clear symptoms but which can infect your Oscar.

The alternative is simple. Grow your own guppies. This will provide you with 2 clear advantages:

  1. Ensure an endless supply of guppies – Guppies are notorious for their breeding capabilities. A healthy guppy female will produce several hundreds of fry every month with proper care and in optimal conditions.
  2. Ensure the guppies’ health – You can provide your guppies with adequate diet and pristine environmental conditions to prevent diseases and parasites. This will eliminate the risks of infecting your Oscar with potentially deadly pathogens.

Where to Buy Feeder Guppies for Oscar?

If you’ve decided to take your chance and grab a few feeder guppies, there’s no shortage of them online. You can go to pretty much all marketplaces that specialize in fish and fish-related products, including Amazon.

If your confidence level isn’t that high, though, you could try to find specialized breeders that offer more warranties than commercial shops. This way, you will, at least, minimize the risk of getting subpar or sick guppies if you can’t eliminate it altogether. If I were you, I would resort to breeding my own guppies.

The advantages always outweigh the downsides.

How to Raise Your Own Feeder Guppies?

I recommend breeding and growing feeder guppies the same way you would normal guppies. In this sense, consider the following:

  • At least 2 tanks – You need one tank for adult guppies and another for the upcoming fry. This will provide you with extra control over the breeding process. Separating the pregnant females from the rest of the adults will increase the fry’s survival rate considerably. Otherwise, adult guppies might hunt and eat them since cannibalism is standard among guppies.
  • Ensure adequate water volume – Each adult guppy requires around 2 gallons of water. So, a 10-gallon tank should only house 5 guppies at most. That would be 1 male and 4 females to eliminate the risk of male-on-male aggression. Even if these are only feeder guppies, they still need adequate space to prevent overcrowding. Otherwise, overcrowding can lead to excess fish waste and higher ammonia levels, which can poison your guppies.
  • Consider proper tank equipment – Guppies absolutely require a heater and a filter. Don’t even think about skipping any of these. The heater is a must since guppies are tropical fish, enjoying temperatures around 72 to 82 F. They hate temperature fluctuations, and the heater will keep their environment stable. This piece of equipment is even more important for the fry since they require higher environmental temperatures to grow during their first few weeks of life. The filter is another vital addition, keeping the water cleaner for longer and oxygenating your guppies’ environment.
  • Decorate the tank properly – Guppies require plants and various hiding spots to retreat to when stressed. This may not seem important, but the problem is that stressed guppies show weaker immune systems, rendering them vulnerable to bacteria and parasites. Pregnant females also require hiding when dealing with pushy males as they tend to harass them relentlessly during the breeding phase.
  • Ensure optimal tank maintenance – Guppies require weekly water changes of maximum 15% of the total water volume. If you have a lot of guppies, you also need to perform regular tank maintenance, vacuuming the substrate and removing algae overgrowth and dirt. The filtering system will also help in this sense. Doing so will minimize the impact of ammonia, eliminate fish waste, and remove food residues and organic matter that could change the water’s chemistry.
  • Ensure optimal diet – Your breeder guppies need to eat well to grow fast and healthy. You should offer guppies a varied diet consisting of veggies and animal-based protein, making sure you keep the protein content low. Guppies are omnivorous and consume more vegetable-based nutrients than animal protein. Feeding them too much protein may lead to constipation and cause health problems in the long run. The fry, on the other hand, could use the excess protein during their first 2 weeks of life. They need the surplus to sustain their accelerated metabolism. Consider personalizing your guppies’ diet based on age and overall requirements.

Don’t be scared if these measures seem overwhelming. If you’ve owned guppies before, nothing I presented here is new. If not, this is a standard care sheet for most tank fish species, including Oscars.

How to Feed Guppies to Your Oscar?

First of all, you shouldn’t feed your Oscar guppies daily. I recommend providing them with some feeder guppies occasionally, probably once or 2 times a week. While Oscars are mostly carnivorous in the wild, they show a more omnivorous diet in captivity. This means that they require a more diverse diet, mixing veggies with animal-sourced protein like worms and various other live food options.

That being said, feeding your Oscar with live guppies or any other live fish is almost a necessity for several reasons. First is that it provides the Oscar with a lot of nutrients to appeal to its semi-carnivorous nature. Second is that Oscars could use the exercise.

Basically, you will feed the Oscar several week-old guppies that have passed the fry stage but haven’t reached full maturity yet either. For a 10-inch Oscar, I recommend throwing in around 6-7 juvenile guppies at once and watching your Oscar hunt them down. The Oscar will appreciate the hunt since it will provide entertainment and tickle its predatorial instincts on the side.

You only need to place the guppies in the Oscar’s habitat, and nature will follow its course really fast.

Risks of Feeding Guppies to Oscar Fish

I would say that the following risks aren’t limited to guppies. They apply to all feeder fish fit for your Oscar, like swordtails, mollies, platies, tetras, goldfish, and others. These include:

  1. The risk of pathogens – We’ve already discussed this point, but we didn’t mention an important aspect here. Your own feeder guppies could develop parasites and infections, especially if you don’t care for them properly. So, don’t sleep on it to think that only commercial guppies have this problem.
  2. The risk of choking – Yes, this can happen, especially if you feed your Oscar larger guppies. To prevent this issue, stick to medium-sized juveniles, which shouldn’t be larger than 1.5 inches at most.
  3. The risk of developing a habit – Oscars love to hunt since it’s in their nature. Feed them guppies too often, and they might develop an addiction to them. This could lead Oscars to refuse dry food like flakes or pellets even when they’re hungry. This issue is more prevalent than you’d think. Only feed the Oscar guppies once a week or even once every other week as a treat.

Generally speaking, so long as you grow your guppies properly, there should be no issue. Your Oscar can’t wait to get some hunting practice.


Oscars will feed on a variety of fish in the wild, and the same behavior transpires in Oscars grown in captivity. If you’ve decided to feed your Oscar live fish once in a while, make sure to get them from reliable sources.

Unless you want to grow them yourself, that is, which I strongly suggest.

avatar Noah
I’m Noah, chief editor at VIVO Pets and the proud owner of a playful, energetic husky (Max). I’ve been a volunteer at Rex Animal Rescue for over 2 years. I love learning and writing about different animals that can be kept as pets. read more...

Leave a Comment

Your email address will not be published. Required fields are marked *