I have a F8 and GSP together at 1.005 sg.

[Froggy416]

Neither have grown significantly in the 1.5 years I have kept them. Originally I had two figure 8s and a gsp. The only other livestock is one bumblebee goby, the brackish kind (you can tell by the stripes).

The tank is 20 gallons. The F8 is about 1.8" in length excluding tailfin, and the GSP is about 1.2" in length, excluding tail fin. I am a bit worried because I thought these guys would grow more in 1.5 years. They are not perceptibly bigger than when I got them. Okay, the GSP is maybe 20% larger. But if the F8 has gotten larger, I can't tell.

Is my salinity right? I have a refractometer now, although I used to use a hydrometer to create "sea water" salinity, and then measure, to dilute down, that was a pain.

The two puffers are doing well, but I thought GSPs would get larger. Someone on my local fish forum has a much larger GSP that is at full marine.

Should I be considering a breakup for this duo? If the GSP grew to 6" I would not have him in a 20g. I know about the overstock situation if these guys do grow, but right now I have less than 4" of fish in my 20g. Will my GSP be happier if I bring him up to full marine and leave the F8 and goby at 1.005? Or is a 1.2" gsp too small to start that at? I know he's at least 1.5 years old. Maybe he's a dwarf gsp!?

Warren
[aka KuhliLoachFan on GTAAquaria]

[bigfatfish]

The simple answer is that the tank is too small for them to grow! All the waste that those guys are putting out, in that size tank will certainly have an effect on their growth rate & probably already has done.
Bigger tank for the GSP & raise the SG & maybe keep just the single F8 on his own in the lower SG tank.

GSPs are very slow growers, so hopefully if you move him now, you may still get some growth.

[Froggy416]

Currently the GSP is being fed once daily, a mix of ramshorn snails, frozen bloodworms, and frozen brineshrimp (both thawed before serving obviously). What could I do to improve his diet? He gets at least one or two small ramshorns a day. He feeds much more voraciously on bloodworms than anything else. I am thinking of live shrimp, gut-loaded with veggies. (I have started a macrobrachium sp. shrimp tank to that end.)

W

[taureandragon76]

Feeding is not your problem whatsoever. F8's and GSP's require different water parameters and they just don't do good in a tank together. The 20g is perfect for your one F8 and BBG, way to small for even a single GSP. As for only having 4" of fish in the tank, that rule is just a general guideline and not something you should really go by when stocking a tank. I would do some more research in the library here.

[jus85411]

throw the "inch of fish per gallon" rule out of the window. its basically to help the LFS sell you more fish because most of the time they dont even know how big the fish they have get. most people think, and i agree with this with certain exceptions(puffers not being one of them) that you should start with the full recommended size tank. so if your interested in a species only tank and you want only 1 GSP, get at least a 30(29 will do) and that way you have no chance of stunting the fish's growth and he will grow properly given that water changes are kept up on and the quality of the water remains in check

[jus85411]

also the reason for such a high minimum tank size recommendation is not just the size of the fish, but based on the bio load the fish will produce. puffers are very messy eaters, therefore food goes everywhere when they eat and waste is produced at such high levels

[taureandragon76]

Also if it has been a year and a half I would say the damage has already been done to that GSP.

I would also be interested to know what your water parameters are like?

[jus85411]

maybe not true. 20 isnt much smaller than the recommended minimum tank size. and if a F8 was the only other occupant, the damage could possibly be reversed. they are slow growers so that is on your side a little. i would focus on getting them separated, or if you dont plan on getting a bigger tank for the GSP, rehome him as he will not be too happy with such a low SG and in such a small tank.

[Froggy416]

The tank is very stable and I never see nitrites or ammonia. Nitrates are usually between 2 ppm to 5 ppm. Algae grows readily in my tank, so I believe it is phosphate rich, but I do not have an RO water system, so it's brackish made from very hard toronto city tap water. Water changes are between 20 and 30% weekly. I use aged hyper-saline water to add the brackish water, as I believe that the reactivity of the artificial-sea-water mix (red sea) is not good for my puffers when I add the salt as salt-crystals (solid) to my tank. So the salt has already been in a bucket of aged pure water, dissolved and ready to add to my tank to top up salinity to 1.005 after each water change.

The 20g has a 110g AquaClear filter, which has massive over-capacity on the filtration, both in turnover (GPH) and biosurface (sponges plus biomedia). I have found this especially important for puffers as they are messy carnivorous eaters.

I think going full marine might be the best way forward, if I can manage it. A 30G with one GSP at full marine, with a protein skimmer and some live rock might be a fun expansion of my capabilities as an aquarist. How fast should I bring him up to high brackish? Should I stop at high brackish and wait, and then move up to some point below full marine salinity, and stop? Or should I aim for a gradual increase week by week, but not pause?

W

[jus85411]

how long has this tank been set up and how did you cycle it? aged hyper-saline water? never heard of this and i just googled it and came up with some germ free, highly salty water that Australia scientists are/were testing to see if it helped cystic fibrosis. would this type of water be puffer safe, is it a marine condition type of water? filtration doesnt really matter that much, dont get me wrong turnover rate is very important but water volume is the most important to dilute wastes/horomones to stop stunting/stressing. you have a good water change schedule, but i think they should be more towards 50%/ week because of the tank size and having a GSP in there, not even counting the F8 and BBG. if you were to get the separate tank for the GSP i would cycle it as marine and drip acclimate him over a couple hours to the salinity you cycle the other tank at.

[Pufferpunk]

I think he just means he's making up some really salty (brine) water & diluting it into his tank to make low-end BW. Correct?

A 30G with one GSP at full marine, with a protein skimmer and some live rock might be a fun expansion of my capabilities as an aquarist

Sounds like a cool adventure into new territory! I assume you will set up the new 30g & not be raising the SG for the F8?