Freshwater Pufferfish: Tetraodon nigroviridis

Common names: green spotted puffer, GSP, spotted puffer, leopard puffer


green spotted puffer

© Freshwater Pufferfish

Activity level: active/hunter

Adult size: ~6 inches

Life span: 10+ years

Min tank size: 30 gallons

Temperature: 74-80 degrees F

pH: 7.0-8.3

Salinity: high brackish-marine


Diet: Hard diet of mostly crustaceans. While your green spotted puffer is a baby-sub adult, you can offer them a regular diet of snails, shrimp, and a variety of frozen foods, like blood worms and brine shrimp. As adults, you can branch out to foods found at the grocery store, like whole shrimp, crab legs, mollusks, and clams. As an occasional treat, you can offer your puffer red wigglers, ghost shrimp, and other types of feeder insects.

Notes: While green spotted puffers are not freshwater pufferfish, I felt that it was important to include a species profile for them. Many pet stores sell GSP as a freshwater puffer, which is unfortunate because they make great aquarium pets – provided that their basic needs are met, like the proper level of salinity in their environment.

It is very important to incorporate a large quantity of hard shelled foods into your green spotted puffer’s diet – their beaks grow at a relatively fast rate, and as a result, they need to be continually filed down. If you don’t regularly feed them hard foods, like snails and whole shrimp, then your GSP will slowly starve to death unless you manually file their beak down.

Green spotted puffers are very active fish that require an interactive environment to thrive in. If they are not provided with enough stimulation, they will continually “glass surf” – in other words, they will swim up and down the glass out of boredom. They are considered an aggressive fin-nipper, and should not be housed with tank mates.


  1. what if the tank is too small? what will the signs be?

    • Freshwater Pufferfish says:

      If the tank is too small, you will risk killing your puffer because the tank won’t be able to handle the amount of waste excreted – ammonia spikes happen very quickly in a small body of water. Generally, if you have to ask if the tank is too small, it probably is!

      A puffer that doesn’t have a large enough tank will most likely pace the glass frequently – some puffers may act the complete opposite though, and become lethargic. You will also see secondary signs that are a result of poor water quality, like ammonia burns, fin rot, etc…

      • Is a 10 gallon tank OK? My freshwater puffer fish is doing great with all of my other fish what do you recommend to feed him?

        • Freshwater Pufferfish says:

          No, a 10 gallon is too small – especially for a GSP (I’m assuming that’s what you’re keeping since this is posted under nigroviridis :) ) A single green spotted puffer should at least have a 30 gallon tank, bigger if you can since they’re very active fish. Ideally, they should be kept in brackish water, as well.

  2. Virgie Smith says:

    I was wondering these white crusty things appeared on my puffer’s eye balls and he can not see how do i fix this??

    • Its called cloudy eye, my fish has it too and I am trying to see how to fix it!

      • Freshwater Pufferfish says:

        Have you tested your water recently? Puffers excrete a lot of ammonia, and if you aren’t keeping up on frequent, large water changes, then that can become an issue pretty quickly. Assuming it’s not age related (old fish commonly have a cloudy appearance over their eyes), one of the most common reasons why fish develop cloudy covering over their eyes is because of poor water quality. However, there are quite a few different things that can cause a fish to have cloudy eyes, including the above mentioned environmental factors, as well as disease and parasites. I would recommend checking out this resource on cloudy eye if you’re having problems with it.

  3. I have a puffer fish that I got from a pet store approx. 4 weeks ago..His/her tummy is no longer white and is kind of grayish…I have been feeding it frozen blood worms ( that I defrost in a shot glass w/tank water) and some nusiance snails that keep breeding in my other tank…his tail is kind of curled and I have been doing regular water changes and I add aquarium salt to the water….he was beaten up a bit at the pet store from some other puffers…what can i do?..

  4. im so confused about aquarium salt vs marine salt which one do i use for my puffs i have three and a pleco in a 55 gallon whats the salinty level supossed to be!!!!!!!!!!!!!!!

    • Freshwater Pufferfish says:

      Hi there :) This is an example of aquarium salt (you’ll find it in the freshwater section of the pet store), and this is an example of marine salt (found in the saltwater section).

      On a side note, a 55 gallon tank is too small for three green spotted puffers, and they won’t be able to be kept with a pleco, either. Pleco’s won’t tolerate the high-end brackish water.

      You’re shooting for around 1.010 SG (specific gravity) in the end. Don’t forget to slowly raise the salinity – your bacteria colony has to acclimate to the new chemistry, as well.

  5. We bought a puffer fish 3 weeks ago and was told that it was a freshwater puffer. I am very disappointed and saddened to find out that my tank is not what the little guy needs. I really like him. :-( Now I am not sure what to do. I can not add salt to the water because I have other fish in the tank. Any suggestions?

    • Freshwater Pufferfish says:

      Aside from finding someone who does have the right tank for him, have you considered setting up a separate brackish tank? You don’t even have to use a glass fish tank, large plastic totes work well, too. Either way, eventually you won’t have many intact fish left in the tank if you leave the puffer in there :)

  6. gina malvezzi says:

    fred is not himself he is not eating and has a dark gray belly he is all so week i have had him for over a month he has brackish water i feed him snails and bloodworms and dried krill please help.

    • Freshwater Pufferfish says:

      I’m sorry things don’t sound like they’re going well for Fred.

      Here are some questions that I would be asking myself:

      1. Where did you get Fred? Was it a reputable pet store? Was he kept with other fish/puffers?
      2. Are you quarantining the live food you’re giving Fred (i.e the snails)? They can introduce parasites if they aren’t
      3. Are you using marine salt or plain aquarium salt?
      4. Was Fred treated for internal parasites? Is he showing signs of ick, or flashing while swimming?
      5. Do you have other fish in with Fred?
      6. What temperature are you keeping the water? How big is the tank? Are there enough decorations/hiding places?
      7. How often are you changing the water? Do you use a quality tap water conditioner, like Prime?
      8. Was the tank cycled first before Fred was introduced? Have you tested the water recently?

  7. Hello I bought a GSP a little over a week ago and I have it in a 30 gallon tank but it is a freshwater tank, with other fish. I was going to see if I could find

  8. Sorry I pressed enter by accident. I am trying to find another tank for him but I was wondering how long do you think I have before he starts having problems?

  9. Despite what is known about puffers, I have 2. One is a leopard puffer and the other a dwarf. Both are kept in the same tank with 5 African Chiclids and an African frog, however no one ever believes that they all live together with out fighting. I feed them all a variety of food from frozen to freeze dried, snails, ghost shrimp, guppies and even blood worms. My dwarf puffer recently has been not eating like he was before. He is healthy looking, belly is bright whitetons of variety to choose from but the only thing he will do now is literally suck the blood out of the bloodworms and.spit the rest out. I’ve done water changes regularly, ph is where it.always has been, nothings changed but his appetite. Please help!

  10. Hi, I’m thinking about getting a puffer. I have a 40 gallon tropical fish tank at the moment, I have the filter and heater and thermometer and lights, but that’s it. I was looking at the freshwaters but the only one I am thinking of getting now is the GSP puffer. What will I have to do to my tank wich has been running for about 6 months but currently has no fish in it, but has water in it that has been in there for about 6 months with the filter working, so what will I have to add to my tank? I’m guessing salt but do I add freshwater salt or marine salt? and anything else I will need to add?
    thanks :)

    • Freshwater Pufferfish says:

      Hi Bob :) Sorry it took so long to answer, I just noticed I hadn’t approved this comment. If you decide to go with the GSP, you would need to add marine salt – the aquarium salt that’s sold in the freshwater section does not create a brackish environment. Make sure you raise the salinity slowly over a period of time because your bacteria need to acclimate to the new water chemistry, as well. When you bring your GSP home, you’ll want to put him in a quarantine tank to make sure you aren’t sabotaging all the work you just did on your established tank :) You can slowly acclimate him to the salinity that your main tank is at while he’s in quarantine, as well, assuming that he was previously kept in freshwater.

  11. Hi!
    I recently bought a GSP from Walmart (not the best place, i know) and he is currently housed in a 20 gallon freshwater tank with a plecostomus. Is he ok with a plecostomus? And how small of a tank can I start him out with (I have to transfer tanks soon) if he’s only like 3/4 – 1 inch long right now?

    • Freshwater Pufferfish says:

      Congrats on your new purchase, they’re amazing little fish. :) You’re right, that’s definitely not a place that should be selling puffers (that being said, we have a F8 that came from Walmart, too, who is now doing very well). Unfortunately, a pleco is not a suitable tankmate for a GSP (assuming we’re both talking about T. nigroviridis) because they cannot tolerate the required level of salt in their water. Your 20 gallon will work fine for the puffer as a single fish for quite a while, although if you get the chance I would go up to 30-40 gallons because they’re very active puffers. Keep in mind that GSP are high end brackish water puffers, so I would personally recommend finding someone who’s willing to take the pleco from you so you can start raising the salinity (very slowly since you’re starting out with freshwater, the bacteria have to be given time to acclimate from freshwater to brackish, too).

      • He seems to be doin pretty good. active. swims around his tank alot. How much marine salt would i need to add to get high end brackish water?

        • My friend just told me that he’s actually acting lethargic recently (He’s staying at his house until i can make room at mine). could this be due to him being in purely fresh water?

          • Freshwater Pufferfish says:

            At this point, probably not. How frequently is the water changed out? Has your friend tested the water recently – if so, what did the reading look like? What kind of diet is he feeding him? Is the water heated? Was the tank fully cycled/mature before the puffer was introduced?

        • Freshwater Pufferfish says:

          Roughly between 1.010-1.015 SG. You will need a hydrometer to measure SG (specific gravity).

          • he’s only been in the tank for 3 days now so I don’t think the water has been changed out yet. I did put some treatment into the water initially to remove chlorine and the like. The tank was cleaned thoroughly after the ciclids that lived in it previously were transfered to a different tank. I don’t think he’s done any tests on the water

  12. I got my green spotted puffer, tetraodon-nigroviridis, about a week ago and my girlfriend and I love him (or her). We named it Chubby Subby. “Subby” is short for submarine because he looks like one when he swims. And “Chubby” because he’s…well…very chubby after he eats. Anyway, I would like to know if it would be better to do his water changes with bottled water, or regular tap water? Thanks

    • Freshwater Pufferfish says:

      Hi there – cute name! I agree, they do look like little submarines. I’m quite fond of calling them helicopter tank puppies, myself :)

      As long as you have a quality tap water conditioner, there’s no reason to use bottled water over tap water. I like to use Seachem Prime on my own tanks. Using bottled water would become pretty expensive over the long run to fill up a 30 gallon or larger tank – not to mention time consuming.

  13. We just bought two little green spotted puffers from a great pet store. They are getting frozen krill and shrimp, but I would like to get them snails for their, teeth, as I have read and done my research..

    I guess my question is, what kind of snails can be placed into a brackish aquarium and what would be the best way to quarantine them so they don’t get my little GSPs (Tazz and Puffette) sick?

    Thanks a bunch.

    • That Fish Lady says:

      It’s wonderful that you’ve done your research, and it’s great that you’re keeping them in brackish water! :)

      As far as snail species go, finding brackish compatible ones isn’t so much of an issue since you’re just dropping them in for feeding time – unless I’m misunderstanding your intent and you want to keep them simultaneously with the puffers? I use ramshorn and common pond snails for all of our puffers; although, I believe nerite snails are brackish (you’d need to double check that). I’ve never been successful in keeping snails in the puffer tanks for extended periods of time.

      When I get new batches of snails to add to my breeding tanks, I separate them into their own quarantine tank for at least a month – I use plastic totes for quarantine usually. Eventually, it would be easier to breed snails in a 5 gallon container/10 gallon tank to ensure you have healthy stock on hand at all times – once the snails have been quarantined initially, you won’t have to worry about it again unless you add new stock or disease is present.

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