Green Spotted Puffer Brackish-to-Marine Transition Experiment

[Reformed1133]

I have a green spotted puffer that started small and grew up alongside some molly fry. Over time, I’ve gradually increased the salinity from 0.005 to its current level of 0.13. My goal is to eventually transition to full marine salinity and keep clownfish with the puffer.

As part of the setup, I’ve experimented with different plants:

• Moneywort: Survived initially but lost all its leaves.
• Bacopa: Didn’t make it.
• Java Fern: Survived but isn’t thriving and looks pretty rough.
• Chaeto (Chaetomorpha): Added when salinity hit 0.09 and it’s doing great.

The tank gets a lot of light. At one point, black hair algae took over, which actually looked cool, but it eventually died off. Green hair algae replaced it and has been thriving. The green hair algae has been fantastic at keeping nitrites in check, allowing me to remove it periodically and rarely do water changes. Since bumping the salinity to 0.13, the green hair algae has started to die off too.

Initially, the molly fry stayed in the tank, but I had to move them out because they were picking on the puffer, even though the puffer is now much larger. Interestingly, the puffer is afraid of the ghost shrimp in the tank!

I’ve been on the lookout for Caulerpa algae, as I’ve read some varieties can handle brackish water, but I haven’t been able to find any yet.

Other tank inhabitants include a few bumblebee gobies, although they haven’t bred so far. I’ve also managed to spawn some olive nerites in the tank, but the babies were eaten over time. I tried adding spiked nerites, but they didn’t survive the salinity increase. I suspect they couldn’t handle the jump as well as the olives did when I added them at 0.08 salinity. I might try spiked nerites again, but I’ll proceed more cautiously next time.

I’ll update this post with progress as things develop!

[Reformed1133]

I also added a mangrove sapling this week. We will see how it does. 

[Chiliboras]

Enjoy the process! I had a gsp about 20 years ago that I started in fresh, then moved to brackish and finally ended up in a FOWLR with a porcupine puffer and some other saltwater fish. Still one of my favorite fish that I’ve ever had.

[Chris]

Love GSPs!

 

Beware their aggression, though - when they mature, they are among the more aggressive puffers. They won't just try to eat things - they will attack them just for existing, lol. My GSP killed a 3" fire clownfish when he was about 2". It really just takes one bite with that beak.

 

Mine also got picked on by mollies when it was young. They do not stay shy like that forever. All puffers are different, but the majority of GSPs are quite aggressive.

 

Personally, I always suggest them to be kept in a species-only tank, or with something like Ceylon puffers that have a similar temperament.