The following species have been recommended by our membership as being compatible Oscar fish tank mates. Along with each species names are notes regarding keeping that species as Oscar tank mates. The intent is not to create a species profile, but simply to give you a heads-up regarding special issues regarding keeping that species with Oscars. As you should with any new fish, please research the species before you add it to your Oscar tank. Simply pasting the species name into Google will normally give you a wealth of information. Note that I have not personally kept many of these species, so just be warned that it is possible that there may be some issues with these species that I am not aware of. I asked for tips from those with more than 6 months of experience with the species, so hopefully, they are fairly reliable recommendations. I note the member who provided the information at the end of the discussion of each species.
If you have any species to add, or additional comments on a species already covered, and have at least 6 months of experience keeping it with oscars, please respond here with the species name, and any special considerations for keeping it with oscars.
Convicts (Cichlasoma nigrofasciatum): Never keep a male-female pair of convicts as Oscar tank mates. Breeding convicts are simply too agressive for Oscars. However, one or more same-sex convicts will do well with oscars. The desired water parameter range for convicts is on the harder side than what oscars prefer, but if your water is somewhat hard already, and your oscars are acclimated to it, the convicts should do just fine. - Saluki
Jack Dempsey(Cichlasoma octofasciatum):) Temperament: An very aggressive cichlid found in South Mexico, Guatemala and Honduras. They can grow up to 8-9 inches on the average. This is a great fish if kept as “single” addition (male or female) to a larger tank. They are very territorial when spawning so I don't recommend adding a pair unless you have at least a 6 ft long tank. Even then, your Oscar may get bullied into the far corner. Water Quality: pH 6.5-7.5, Temp 72-77 deg fahrenheit (although they do well at temperatures closer to 80 deg fahrenheit). Food: They are omnivorous so watch your plants. Mine are also partial to crickets, worms, shrimp, krill, pellets, flakes, zucchinis and peas. - dvross
Severum: Severums are generally peaceful, at least by cichlid standards. They also get nearly as large as an Oscar. In general, Severums can be considered one of the preferred tank mates for Oscars provided the tank is large enough. - Kmuda
Tinfoil Barbs (Barbodes schwanenfeldi): This is a large (about 12 inches SL) schooling fish that my oscars pretty much leave alone. I have kept a trio of them with my oscars for a little over a year. I would recommend a minimum of 3 for their comfort, so you would need a fairly large tank to keep them with a pair of oscars. My tank is a 120 gal, and is virging on being too small for the two oscars and 3 tinfoils. -Saluki
Silver Dollars (Metynnis hypsauchen): These are medium sized schooling fish from South America. They come from similar water types as oscars, and seem to be tolerant of a wide range of water conditions. They are pretty shy, and do best in schools or 5 or more. Since they get fairly large( up to 8 inches ), they need a bigger tank for a school. I would not keep them in any tank less than 48” long, as they are fast swimmers, and need a lot of room. My oscar largely ignores the silver dollars, but even if he wanted to pick on them, they are way too fast for him. They should be fed primarily vegetable matter, and mine love to eat algae wafers. They will eat anything, and often sneak up and steal some of the hikari oscar pellets.- RoadDogMM
Spotted Silver Dollar (Metynnis maculatus): Temperament: A South American vegetarian species, also a peaceful schooling fish so keep 3-4 together for their well being. They are hard on live plants but are known to dislike Java Fern and Java Moss to some degree so they may be safe - but no guarantee. Water Quality: 75-82 degrees, neutral pH (can tolerate neutral to acidic). Food: Flake or pellet with vegetable based supplements or actual vegetables (zucchini and romaine lettuce). They also like shrimp and worms, both frozen and freeze dried. - dvross
Bala Shark (Balantiocheilus melanopterus): My tank: They have been in the same tank for almost 6 months now with no issues. The Oscars and shark where 3” at the time they where added to the new 100gallon tank. The O's have grown quite quickly and could easily give the shark a LOT of issues if they wanted to. But there have been NO issues at all; they don't seam to bother the shark at all. Generally though the shark is smart enough not to bother the O’s either, generally swimming away when the O’s come around. I have loved having this fish in my tank, just ads some extra something in the tank to look at. Conditions: about the same as Oscars. Food: They love blodworms, but have been doing well on leftover form the Oscars pellets. They will eat almost anything edible. Temperament: a fairly timid fish, prone to darting rapidly around the tank if startled, and they tend to get startled quite easily by sudden movements. They are very peaceful and get along well with other species. On the odd occasion, they may briefly chase another fish around, almost playfully, or if it is annoying them, but never anything more. Size: Supposed to attain a maximum length of around thirteen and three-quarter inches. So these fish get as large, if not larger, than an Oscar. So these should not be used in anything but the largest of tanks.
Common pleco (Hypostomus plecostomus): A great compliment to an oscar tank. Note, however, that as a pleco gets bigger, so does its waste. Do not place a pleco in a tank because you think it will magically make your tank clean. This simply will not happen. Because they are quite agressive toward others of their species, do not place more than one pleco in any but the largest tanks. Also, if your oscars begin to breed, you should remove the pleco. They love caviar. -Saluki
Clown Loach (Botia macracanthus): A very discriptive name for one of my favorite Indonesian bottom dwellers. They grow to a maximum length of around 17” in the wild and typically 6-12” in captivity, live as long as 20 years and are most happy in larger groups. Keep at least 3 but 5-7 are preferred if you have the room. They are very peaceful fish and are alot of fun to watch. They will actually play “dead”, laying on their sides or upside down! It is said that you can sometimes hear them making a clicking sound which I thought I've heard on occasion, but won't swear to it. Requirements: They need a large tank, 90 gallons minimum and 125 gallons preferred. They like alot of hiding places so give them plenty of rocks, caves, etc. They are “snufflers” so they like a softer substrate to allow them to root around for food. Temp: 77-86. pH: Not specific, can tolerate a very wide range (They are even good tankmates in African setups.). Water hardness: Softer is preferred. Food: They will eat darn near anything from pellets to plants to frozen foods. Use caution with certain medications. Make sure they are safe for scaleless or 'ornamental' fish. - dvross - Added by ksb: I second clown loach. In my experience they are excellent tankmates for aggressive fish. They can get bullied and pushed around but they don't care. In the end, they usually get ignored. However, they get ich easily.
Pictus Catfish (Pimelodella picta): I'm currently keeping three Pictus Catfish as Oscar tank mates. There's a lot of conflicting information about pictus….according to sources I've found on the net, they can grow anywhere from 4 inches up to 10 to 12 inches. The more common numbers I'm finding is around 6 or 7 inches. This is probably also due to there being two different variations of pictus catfish….a Columbian variety, and a Peruvian variety…….one of which grows bigger than the other. As far as care, they do very well just cleaning up after my O's….in fact sometimes I'm surprised at how fast they clean up the left overs…..and they really get to flashing around the tank when they do this. On occasion, I do give them some jellied blood worms….and one of them has even learned how to go to the top of the tank and eat whole pellets!!! They also seem to be somewhat hardy, as I recently had one that swam headfirst into the python while it was laying against the gravel siphoning. I was working at the other end of the tank when I noticed him. Well, his mouth was sucked up against the smaller part of the tub inside the large gravel cleaning tub, so much so when I turned the python off I had to shake it to get him un-stuck. Well….somewhere in the process he lost literally half his tail, and all the way around his mouth was red from blood under the surface of his skin from the suction. That was on Sunday, and he's doing fine….tail is already starting to grow back, and all the redness around his mouth is gone. Environment wise, they do well in the same temp of water as my O's, and prefer pretty much the same water parameters as O's. That's part of the reason I went with them…..both species were from South America. Here's a few links to more info about Pictus.
http://web.archive.org/web/20061029133159/http://www.suite101.com/article.cfm/14243/85764 http://web.archive.org/web/20061029133159/http://www.users.bigpond.com/rjeb/pictus.html http://web.archive.org/web/20061029133159/http://freshaquarium.about.com/library/profiles/blfw0006.htm http://web.archive.org/web/20061029133159/http://fish.orbust.net/pictuscatfish.html - raregtp
African Brown Knife (Xenomystus nigri?): I've had an African Brown Knife with my first Red Tiger O for about a year and with my second Red Tiger O (bought at 8”) for about 4 months. Both O's totally ignore the Knife unless they have eggs, and then they chase him off if he gets close to the eggs when he comes out of his cave. The Knife is a nocturnal scavenger, and needs a place to hide during the day and/or when the lights are on in the tank. I bought a piece of fake wood from Petsmart that's hollow on the inside with a hole in each end – the Knife immediately took up residence in there. My Os also like to sit on the bottom behind the same piece of fake wood, so it works out pretty well. If you have a breeding pair of Os I'd recommend removing the Knife when your O's have eggs. They like the eggs and I feel sure they would eat the fry as well. I personally choose to remove the eggs after they are fertilized (I have a plec in the tank as well). - MattR - Note from Saluki: These fish can get over 2 feet long. Only buy them if you have the space to keep them.