Filed in Brackish on May 21, 2014 with 7 comments

A trip to my local fish store (LFS) last week turned into an adventure in setting up my first brackish aquarium. They had just received a shipment of figure 8 and green spotted puffers. How could I resist? This is how I prepared the brackish aquarium for the new puffer.

Setting up a brackish tank

Figure 8 and green spotted puffers start spend a great deal of their natural lives in freshwater and many fish stores sell them as a freshwater fish. However, their natural environment is where the rivers meet the ocean so they do best in a brackish aquarium.

Brackish tanks are saltwater tanks with less salt than your typical reef or marine aquarium. Reef and Marine aquariums are kept at a salinity of 1.024 – 1.026, whereas brackish tanks are kept at around 1.005 – 1.008.

UPDATE: reddit.com user, 4rch, had a great tip for people who have existing freshwater tanks that want to convert to brackish. You should make the conversion slowly so that you don’t kill the bacteria. This is done through slowly increasing the salinity through water changes. After a little searching around it seems a good rule of thumb is to increase specific gravity (salinity) by 0.002 every week through water changes until you reach the brackish range of 1.005 – 1.008

To setup a brackish tank you should use the same salt mix that is used to setup a saltwater tank. I used Instant Ocean marine salt mix for my setup. You will also need a hydrometer to test the salinity of your tank to make sure you have the mix right.

Puffers are a messy fish and so the rule of thumb of one gallon per inch of fish doesn’t apply to them. The ideal setup is five gallons per inch of fish but that is just the bare minimum. Ideally you want the largest tank you can afford and/or convince your significant other to let you have. Here are some quick stats about these fish to help in deciding on the size of tank you should purchase:

Figure 8 Puffer

Size sold: .5 in. – 1.5 in.

Max Size: 3 in.

Max Age: 15+ years

Minimum Tank Size: 15 gallon

Best Tank Size: 30+ gallons

Green Spotted Puffer

Size sold: 1 in. – 2 in.

Max Size: 6 in.

Max Age: 15+ years

Minimum Tank Size: 30 gallons

Best Tank Size: 90+ gallons

Once your water is prepared, you still have to cycle the tank as you would with any aquarium.

Cycling a brackish tank

Cycling the tank works the same as both it does in both freshwater and saltwater aquariums. You need to allow the bacteria to get established in your tank before introducing the new fish. Typically this process can take about a week.

If you don’t know how to cycle a new aquarium you should read this excellent article on how to fully cycle your tank without using fish: Fishless Tank Cycling

Including proper tank decorations for a puffer

Puffers are highly active fish, but like all fish they are prone to stress related illness, so they need to feel secure in their new environment. The best environment is a sand or gravel substrate with lots of live or plastic plants for them to hide in. It would also be a good idea to give them some sort of cave that they can hide in.

All species of puffer are aggressive even to their own species. It is a good idea to have lots of hiding places if you plan on having more than one in the same tank. Of course individual behavior varies greatly so you won’t know how tolerant an individual puffer will be with other tank mates until you get them.

Acclimating your new Puffer

My LFS had the puffers in freshwater aquariums with just a mild amount of aquarium salt in them. Since my setup was a fully brackish tank I had to slowly acclimate the puffer to the new tank through drip acclimation.

It took about an hour to acclimate the new puffer to the brackish water. Once acclimated I put him in the tank and he immediately began exploring the tank. Puffers are highly active and curious fish. Here he is checking out the heater in his new tank.

Feeding the new Puffer

Puffers mouths have teeth that never stop growing. They need crunchy food, like snails, shrimp, mussles and crabs, to wear down their teeth or their teeth may grow so much that they are unable to eat. If you notice your puffer having trouble eating you can trim their teeth using the process seen is this video:

That’s what I have learned so far about keeping a figure 8 or green spotted puffer fish. If I missed anything or got anything wrong, please let me know in the comments below and I will update this post.