Oscar Fish Tankmates

If your aquarium size permits, you might want to consider adding some tank mates in with your Oscar fish. Now this is very important, don't go to your fish store and buy the first fish that takes your fancy. Careful consideration must be taken when choosing tank make for the Oscar fish. I'm sure it's not gone unnoticed that Oscars have got very big mouths, they will try and eat just about anything that they can fit into their mouth. Many people buy small catfish such as pictus, or bristlenose, these fish don't really get much bigger than about 5 inches and are often purchased at half the size, a really nice tasty snack for a hungry Oscar. Some catfish have spikes on their fins that can quite easily get stuck inside an Oscars mouth, in fact on more than one occasion we've had to advise people who have had just this problem. Three important factors should be taken into account when choosing fish that are going to share a tank with your Oscar Fish. They should be big enough so the Oscar will not look upon them as food. The fish also has to be capable of getting out of the way of an Oscar because they do have a reputation of being bullies at times. Finally, you need to choose fish that can compete for food, feeding time can be a frenzied all for one and one for all so your tank mates must be able to feed if you don't want them going hungry.

A few suitable tankmates

Synodontis Catfish - 7"  

The Synodontis Catfish is nocturnal so maybe active at night. Avoid catfish less than 6 inches as some have nasty spikes on their fins

Silver Dollars - 6"  

Silver Dollars like being in groups. They are extremely placid and make excellent tank mates. Make sure that you have a supply of vegetarian food if you keep silver dollars

Severum - 12"  

Severums really do make excellent tank mates for Oscars as they can stand up for themselves perfectly okay and are more than capable of competing for food

Jade Eyed Cichlid - 6"  

The Jade Eyed Cichlid is a Central American cichlid which also makes an excellent tank mate for Oscars as they too can stand up for themselves perfectly okay

Chocolate Cichlid - 12"

Chocolate cichlids have a peaceful nature and make fairly good tank mates for Oscars if size permits

Pumpkinseed - 5 to 7"

Found in the great Lakes of the USA, Pumpkinseeds can make suitable tank mates for Oscars

Banded Leporinus - 12"  

I absolutely adore my Leporinus, they are not aggressive and keep themselves to themselves. However they can occasionally nip at other fishes fins but it's not something you should worry about. They can be a little timid and skittish so any sudden movements in front of the tank will startle them. These fish absolutely love peas

Satanoperca jurupari (Earth-Eater) - 10"  

These Earth Eater fish are very placid & like being in groups, from my experience they don't do very well on their own. They will eat sinking food and blood worm so can compete for food easily. If you have a group of them they are fantastic addition to your aquarium

Blue Acara - 8"  

These little chaps although quite small are more than capable of standing up for themselves, from my experience they get more aggressive the older they get

Jack Dempsey - 10"

The Jack Dempsey fish is a semi-aggressive cichlid that and will make a good tank mate for your Oscar as they are more than capable of picking up for themselves and competing for food

Firemouth - 8"

This relatively small cichlid that doesn't normally exceed 8 inches is another fish that will more than stick up for itself if sharing a tank with an Oscar

Obviously there are many more fish that you could put in with your Oscar, these are just a few Examples of the more common tank mates that people keep with their Oscar fish.

The sizes quoted on this page are meant to give you an idea of how big these fish can get. It isn't guaranteed that these fish will get this big in your aquarium. If you are unsure about what fish to mix with your Oscars then please visit our forum and seek advice...

Choose Tank Mates Carefully

Oscars like to be boss. They may well try and bully other fish but as long as they are capable of getting out of the Oscars way pretty smartish, you should be okay. There are various fish that could pose a problem if mixed with Oscars, some of them are the Jack Dempsey, Terrors, Flower Horns, Parrotfish and Blood Parrots. Apart from the latter, all these fish can be very aggressive. Blood Parrots may have difficulties defending themselves which could result in them not being able to compete for food. Some people don't have a problem with mixing these type of fish, it's just something you should bear in mind. Just let me reiterate what I said about putting small fish in with Oscars. If you want community fish such as Tetras, Mollies etc, put them in a tank of their own because they probably won't last very long in with the Oscars.

Fish Can Often Be Territorial

Rather like cats and dogs who guard their territory, many fish, cichlids especially will often lay claim to an area of the aquarium and will get very aggressive towards other fish encroaching on "their patch". One example would be my 5 inch Blue Acara, he has decided that the area at the back of the tank behind a large piece of wood belongs to him, he very rarely ventures outside of this area even though his tank is 8 foot long and 350 gallons. If any of the other fish, including Oscar's enters this area, he will try and see them off and isn't happy until they are gone. So the point I am trying to make is that if you are going to keep different species of fish together, especially various types of cichlids, trying to keep them in a small environment could be fraught with difficulties.

You have to remember that the total body mass of of fish will determine how much bio-load will be put on your biological system. To put it simply, the amount of ammonia that your nitrifying bacteria is able to process. If the bacteria can't keep up with the waste that your fish produces, dangerous toxins could well start building up in the tank water. This is where health problems could start.

We have already established that 55 gallons is the absolute minimum that you would want to keep an adult Oscar fish in. Two Oscars will obviously roughly twice the space, definitely no less than 100 gallons.  Let's go back to the total body mass of a fish. An adult Oscar can be very big, it has a large body mass. Not only do Oscars grow to quite impressive lengths, they also have deep bodies as well. Oscars normally only reach around 12 inches in captivity. If this is the case, you may calculate that half of 12 is 6 and determine that you can only have a couple of 6 inch fish.. This isn't necessarily the case. Let's look at pictus catfish for instance. These can reach five or 6 inches. That is half the length of a 12 inch Oscar. However, it is by no means as deep, in fact it, an Oscar is probably four times the height of the pictus catfish, so you can see that you could probably have four or five pictus catfish in with one Oscar as four or five pictus catfish will produce around the same amount of waste as one large 12 inch Oscar. In fact, I would say an Oscar of that size will produce a lot more waste. And since pictus catfish to do well in shoals, these make ideal tankmates, as long as they are adults are not small mouth size snacks. I have included a shortlist of other suitable tank mates, I'm not going to confuse you, after all this website is aimed at beginners so use your initiative, if you've got 100 gallons then it goes to say that you are okay with one Oscar and a Severum, it's as simple as that. It's not okay to put three Oscars and a Leporinus in a 100 gallon tank because there is not enough room.

Some cichlids can be very aggressive, so mixing them has to be thought through thoroughly. For instance, I wouldn't recommend putting a green terror in with your Oscar, that could well be a recipe for disaster. I have already mentioned that Oscars will eat anything that they can get in their mouth, so putting in a shoal of neon tetras would be a pretty stupid thing to do. Whatever you put in with them, make sure they are at least 4 in. long. Silver Dollar's, tinfoil barbs (not too many as these do get quite big) some species of cichlid are all suitable for a large Oscar Tank. I have got a jade cichlid and I have no problems whatsoever, it is a beautiful peaceful little fish.

There are various catfish which make suitable tankmates for Oscars. if you do choose a catfish, I would strongly advise you to go for a fully grown adult. Pictus catfish are common amongst aquatic enthusiasts and are a nice addition to any tank. These little catfish normally reach around 5 inches. If you do choose one of these, try and go for one that is at least 4 inches, preferably more.

Beware of Catfish

We already know that Oscars have got big mouths and they can get a lot in them. They are greedy fish and sometimes have eyes bigger than their belly. They will often grab hold of things that they have absolutely no chance of swallowing. The problem with some catfish is they have spines located on various parts of their body, especially on their dorsal and pectoral fins. These spines can be extremely sharp, some catfish have spines that are sharp enough to penetrate the bottom of somebody's shoe. What can happen is an Oscar grabs hold of the catfish, realises it can't swallow it and then tries to expel it. This is when problems can arise.

Fish normally swallow their prey headfirst so that fins such as a dorsal fin don't get stuck in their throat. Unfortunately, what goes down easily doesn't always come out as well. When the Oscar tries to expel the catfish, the spines can get stuck in either the fish's throat, or its mouth. In a lot of circumstances, the Oscar will manage to release the catfish. In a small number of cases, it just cannot budge it. When this happens, you have to take immediate action. If you are a confident person, remove the Oscar from its tank and take the catfish out of its mouth. If the catfish's spines have penetrated the Oscars mouth and you can't pull the catfish straight out of the mouth, you will have to remove the spines from the catfish. A pair of manicure scissors are excellent for this task, if you haven't got any of these to hand, something equally as small should suffice. Snip the spines and remove the catfish.

One of our own members had this exact problem. His Oscar tried to swallow a catfish and it got stuck. The spines actually penetrated the bottom of the Oscars mouth. He had to perform minor removing the spines from the unfortunate catfish, which meant he could remove it from the Oscars mouth. Luckily, the Oscar lived to tell the tale. So you see that choosing tankmates is very important. Oscars can and will try and eat their tankmates if they think it is a viable meal.

Check the Size

Pleco are readily available in many fish stores, they are normally sold cheaply as small juveniles. Most shops do put labels on their shop tanks stating how big the fish get, however people often overlook this important fact. There are lots of different species of plecs available, some of them don't get much bigger than 6 inches, however the cheaper common and sailfin variety can easily exceed 18 inches, sometimes approaching 2 feet and more, these are often the ones you find for sale in the shops at a very small size. The larger species of plecos produce an enormous amount of waste as they are constantly feeding on algae. They can also get very territorial which can be a serious problem as they are primarily nocturnal so can create a lot of disturbance when all the other fish are sleeping. My own personal advice would be to avoid the larger species in this fish range, unless you've got a very large aquarium they are just not suitable. If you really want one of these fish then my advice would be to do some research and explore the possibilities of obtaining the ones that don't exceed 8 inches in size, they are available but you will have to search around, they can also be very expensive as well.

Finally, just let me mention another fish that some people buy when they are very small and then get a shock when 12 months down the line, that 3 inch fish is approaching 24 inches. This fish very much resembles a piranha, it's not surprising as it is a member of the piranha family. However, the Pacu is a gentle vegetarian, or should I say a gentle giant vegetarian. Whereas shops normally only have them for sale after people have bought them as juveniles only to discover what they have got themselves into and can no longer keep them in their small aquarium. The best advice I can give you is avoid these fish unless you are an experienced fish keeper, in that case you don't need me to tell you about how to keep them responsibly.