A Brackish water fish is a fish that survives in water that is part saltwater and part freshwater. These species of fish thrive in rivers where the river and ocean meet causing a mix of salt and freshwater.
These fish have a high tolerance for sudden swings in the salinity levels in water. Brackish fish are very hardy fish for this very reason.
Even though Brackish fish do well with increases and decreases of saltwater and freshwater levels they do prefer a steady salinity level of around 1.015. Keep your levels close to that and you will have happy and healthy Brackish fish.
If you are new to Aquariums you might be surprised at what fish originated from Brackish waters because some Brackish fish have adapted and can live in freshwater tanks.
So where is Brackish water found exactly and what causes brackish water?
Brackish water is found at the ends of rivers that run into Oceans, they are found in Estuaries, Deltas and Swampy regions that separate the Oceans from the Rivers.
Some of the most popular and hardy Brackish fish for the home aquarium hobbyist are listed below.
If you are going to have a small aquarium for your new Brackish set-up then this will be a great fit for your small tank. Bumblebee Gobies are very small bottom dwellers.
Bumblebee Gobies are native to Southeast Asia (mostly Thailand, Vietnam and Indonesia) found in the ends of rivers, streams and in mangroves.
These Gobies don’t usually grow any longer than 1.5”s. A few of these little guys in a 10 gallon tank would look incredible. They are long with roundish bodies and have a large mouth for the size of the fish. Bumblebee Gobies are mostly blotchy black with blotchy yellow looking stripes.
When you look close at a Bumblebee Goby, it looks as if the body is yellow with black stripes but some hobbyists see that flipped when they look at this fish. So you be the judge of its markings when you get one. You can have them in a community tank as well as a tank filled with Bumblebee Gobies.
Bumblebee Gobies are not aggressive fish. They are very peaceful but do prefer if other fish stay out of their favorite hiding places. These Gobies prefer a tank setup that has lots of rocks and plants as well as little caves or some sort of hiding place that they can quickly dart into if they get scared.
If you want to try your hand at breeding Bumblebee Gobies try doing a 20% water change and add freshwater only back in the tank. This is a great way to induce spawning.
When feeding your carnivorous Bumblebee Gobies make sure to provide smaller live foods if possible however freeze dried or pellets will work as long as they are bloodworms, Tubifex worms and some brine shrimp.
Figure 8 Puffer Fish
The Figure 8 Puffer is a bit aggressive towards its own species so consider owing only one of these fish if your tank is small. I wouldn’t recommend having this puffer in a tank any smaller than a 30 gallon. If you want more than one figure 8 puffer in the tank then the tank should be 50 gallons or larger.
The Figure 8 Puffer is native to Southeast Asia such as areas like the Mekong and can be found in freshwater to Brackish water. On average they will grow to approximately 3” in length. The coloring and patterns on this fish are very interesting. On the top side there are greenish yellow markings as well as some black spotting. The underside is white.
A figure 8 Puffer fish can survive in freshwater and saltwater but will live longer (possibly over 10 years) in a tank with a salinity around 1.005 to 1.008.
Figure 8 Puffers can be kept in the same tank as Bumblebee Gobies. Figure 8 Puffers are molluscivores so they prefer foods such as mussels, Krill and Oysters. You can also feed them freeze dried and pellets if necessary however the proper foods for this species should be included more than 50% of the time.
Scatophagidae fish family can be found in Thailand and other indo-Pacific regions. They are found in the ends of streams and rivers as well as mangrove swamps.
There are other types of scats however I seem to find more Green Scats than any others available to purchase at local aquarium stores.
Green Scats are a brackish fish with blackish spots all over its body and the rest of the coloring is a Dark Green with a brownish bronze color.
This fish is always underestimated on what size of a tank it requires. When you purchase a Green Scat fish at the fish store they are usually 2 or 3 inches long so they aren’t very big when young.
Most newbies to aquariums don’t realize that these fish can grow up to a foot long when they mature. This means a Green Scat should probably end up in a 100 gallon to 125 gallon.
When you first purchase a 2 to 3 inch young Green Scat you could keep it in a 50 or 55 gallon but should move eventually to a larger tank.
The Green Scat prefers water that is closer to saltwater than brackish water however when they start out they are brackish. Interestingly when the pregnant fish spawn they do it in saltwater. Just to confuse you a bit.
The salinity for this tank should be 1.015 or higher if possible depending on what other species share the aquarium.
Scats like to have lots of plants so makes sure to invest in some brackish plants. A warning though to stay away from Java Fern for this fish’s tank as the plant is toxic to the Scat fish. Some plants that definitely do well in this environment are the black, white and red mangroves which are types of trees and shrubs. They could be grown and trimmed in a brackish tank quite easily.
Green Scats are omnivores and enjoy a nutritious diet of dried seaweed, algae flakes, fresh lettuce, brackish fish flake foods, frozen brine shrimp and meat based foods.
Sebae Mono Moonyfish
Monodactylus Sebae or Sebae Mono the moonyfish can be found in mangrove swamps, estruaries, lagoons and the Atlantic Ocean off the west coast of Africa.
The Sebae Mono is a silvery white with distinct black lining. They grow anywhere from 6 to 9 inches from top to bottom in captivity. You could say that these fish have a diamond shape to them.
The Sebae Mono like the Green Scat will need to be kept in a large aquarium. When they are young you can keep them in a 50 or 55 gallon but as they grow a 100 gallon to 125 gallon should be the size of tank the fish is placed in. These fish require a lot of room to swim around.
A young Sebae Mono might prefer a tank on the freshwater side and as they grow older adding more salt increasing the salinity is preferred by this fish.
Make sure to have brackish friendly plants in the tank as well as lots of rocks and hiding places.
The Sebae Mono eats similarly to the Green Scat preferring dried seaweed, algae flakes and fresh lettuce. Also offer your Mono some frozen brine shrimp and a flake food manufactured for brackish fish.
There are many other types of brackish fish available to the home aquarium hobbyist. This short list is put together with the thought that these are true brackish fish. I feel that if you truly want a brackish tank then these selections will be a beautiful display of what a brackish body of water would hold for inhabitants.
I say that because some other brackish categorized fish can be found in only freshwater tanks at your local pet stores so some hobbyists might not even know they are actually a brackish fish.
Some of these other fish include Mollie’s, glass fish, archer fish, orange and green chromide’s, fiddler crabs and Colombian catfish. There are other brackish type fish however this list should cover the vast majority sold in stores.
Want to learn about some really cool hardy freshwater fish for a small tank?
Or how about learning about my recommended saltwater hardy fish?