Top 7 Warm Water Fish That Aren’t Afraid of a Little Heat

During the hot summer months, it can be hard to keep your aquarium water cool enough for certain fish. Fortunately, there are some species that can survive in higher-than-normal temperatures. Just remember that warmer water cannot hold as much dissolved oxygen as cooler water, so reduce your risk of oxygen deprivation by adding an air stone, sponge filter, or other form of surface agitation. Also, look for aquatic plants that can tolerate higher temperatures, such as anubias, java fern, bacopa, sword plants, and micro swords. With all the caveats out of the way, let’s talk about our favorite warm water fish and invertebrates that you should try. 

1. Discus

Symphysodon spp.

The “king of the aquarium” is a gorgeous cichlid that comes from the Amazon basin in South America and enjoys temperatures of 84–86°F (29–30°C). While some hobbyists prefer to keep them in softer water, we personally find that they do well in pH levels from 6.8–7.8 and soft to medium hardness. Discus have a large, circular shape and can grow to the size of a 5- to 7-inch (13–18 cm) plate. In a 75-gallon aquarium or larger, we like to keep a school of six discus, along with some other community fish from this list. Because they have small mouths, they enjoy feeding on bloodworms, Hikari Vibra Bites, and all sorts of frozen foods. For more information on how to keep them healthy and stress-free, read our full article here.

2. German Blue Ram

Mikrogeophagus ramirezi

This dwarf cichlid from Southern America is known for its brilliant, rainbow colors that rival those of saltwater fish. They stay around 2–2.5 inches (5–6 cm) long and come in many varieties, such as regular German blue, gold, electric blue, and black rams. They must be kept at high temperatures, ideally between 84–86°F (29–30°C), and prefer softer water with low GH. A pair of rams can live in a 20-gallon community tank or in a 10-gallon species-only tank with no other fish. When preparing a specialized breeding setup, we’ve had good success using bare-bottom aquariums with a lid and background to help them feel safer. Use a gentle sponge filter to prevent fry from getting sucked up, and place flat river stones and tiny terracotta pots in the corners of the tank as spawning sites. For more information on breeding and feeding these beautiful cichlids, check out this care guide.

3. Rummy-Nose Tetra

Hemigrammus rhodostomus

This active South American tetra is known for its tight schooling behavior, black and white striped tail, and gorgeous red flush on the face. They get the nickname of “canary in the coal mine” for aquariums because their ruddy snout fades in color when they are stressed, which can serve as a visual warning sign for bad water quality, low temperatures, disease, bullying, or other problems. Despite their smaller size of 2 inches (5 cm), we recommend keeping them in a 20-gallon tank or larger to give them lots of room to swim back and forth. They can live in temperatures between 74–84°F (23–29°C), pH of 5.5–7.5, and soft to moderately hard GH. A school of 8–12 tetras or more would serve as a great dither fish for shy or territorial fish like Apistogramma dwarf cichlids. Read more about them in our detailed article.

4. Sterbai Cory Catfish

Corydoras sterbai

The 2.75-inch (7 cm) sterbai cory is extremely popular because of its high contrast spots, horizontal striping, and orange pectoral fins. They can live in a wide range of water parameters, such as pH of 6.0–8.0 and temperatures around 75–82°C (24–28°C). This schooling fish does well in a 20-gallon community aquarium or bigger with other similar-sized, peaceful animals — such as tetras, pencilfish, and snails. As with most corydoras, they are bottom dwellers that do a wonderful job of cleaning up the substrate, but they cannot live on scraps alone and must be specially fed sinking foods such as wafers, frozen bloodworms, and Repashy gel food. When given plenty of food to eat, they may start spawning and laying eggs for you.

5. Clown Loach

Chromobotia macracanthus

As the largest fish on our list, these 12-inch (30 cm) gentle giants love to play with each other and have many funny behaviors — like piling on top of each other in tight spaces, lying on their sides to sleep, and making clicking noises to communicate. While juveniles may be kept in 55- to 75-gallon aquariums, many hobbyists recommend keeping a school of adults in an aquarium that is at least 6 feet (1.8 m) long. Our #1 recommendation is to always keep the water at 82–86°F (28–30°C) so that they stay healthy. Many of them are transported in cooler temperatures and therefore may fall ill to ich (or white spot disease) or other infections, so make sure to quarantine them upon arrival and treat them with medication as needed. They go well with other peaceful species of a similar size but will eagerly eat any snails or shrimp that they can find. For more information, see the full article.

6. Zebra Pleco

Hypancistrus zebra (L046)

This beautiful but reclusive pleco is highly valued for its striking, black and white stripes, but it is critically endangered in the wild and therefore hard to find in local fish stores. Many dedicated hobbyists have tried to breed them, but success has been difficult with low yields. In terms of regular care requirements, this 2.75-inch (7 cm) catfish can actually live in a wide range of environments with both low to high pH and GH, but they do prefer warmer waters from 80–86°F (27–30°C). As an omnivore, they eat both proteins and plant matter, but many breeders recommend feeding live and frozen meaty foods, as well as carnivore pellets that are high in healthy fats. While they can live in a community setting, a species-only setup with strong current and lots of pleco caves is preferred for colony breeding.

7. Cardinal Sulawesi Shrimp

Caridina dennerli

We fell in love with this 1-inch (2.5 cm) dwarf shrimp because of their deep red color, white spots, and white front legs that are constantly moving and look like they’re dancing. They originate from Lake Matano, the deepest lake in Indonesia, which is known for having temperatures of 80–88°F (27–31°C), higher pH around 8.0, and 6–12° (100–200 ppm) GH with plenty of minerals for healthy exoskeleton molts. Like the zebra pleco, it is critically endangered in the wild, comes with a high price tag, and is sought out by experienced aquarists for breeding purposes. To keep the water parameters as stable as possible, many breeders recommend using a mature, species-only aquarium of at least 10- to 20-gallons with a high-quality heater and temperature controller to notify you if the water is too hot or cool. Like your typical dwarf shrimp, they feed on algae, biofilm, microfauna, and decaying organic matter. Offer them a variety of fish and shrimp foods so they get all the necessary vitamins and minerals they need. 

We hope you are inspired to try some of these lovely and unique warm water species. While we do not ship fish, you can check out our preferred online retailers to see what they have in stock. If you live in a colder climate or are interested in keeping unheated aquariums, learn about our top 10 cool water fish that like lower-than-normal temperatures.