Help Please?

Tank size: 10gal [sick tank: 2 1/2 gal]
I know their tank is small but its the only one I can fit and afford and they've been completely happy until now. And they actually used to be absolutely content in their own individual 2 1/2 gallon tanks.
pH:
ammonia:
nitrite:
nitrate:
kH:
gH:
tank temp: 78-82 degrees

-Sorry I don't know the exact numbers for the ammonia, nitrite, nitrate, etc.. I tested the water with one of the ammonia kits from the pet store and it showed that it was safe.

Fish Symptoms (include full description including lesion, color, location, fish behavior): I have two green spotted puffers, one is PuffPuff [he's the bigger of the two at about 1 3/4 in] and Puffy is about 1 1/2 in. PuffPuff has been very bloated and just laying at the bottom of the tank for the past 3 or 4 days and wasn't eating.. [He's usually a PIG. hehe] so I moved him over to my sick tank and treated him for parasites. [The tablet meds that they sell at the pet store: its called Jungle Parasite Clear Tank Buddies and I used the amount recommended, 1/5 of a tab for 2 gals] Since then he seems a lot happier; swimming around and playing in his bubbles as usual, but still not eating.. Puffy was perfectly healthy and happy until the day after I moved PuffPuff to the sick tank. Now he's either laying in his sand or hiding under the filter and when I go up to the tank he gets scared and zooms across the tank and almost rams into the wall. He's never been like that before and I've had him for 4-5 months already. [I've had PuffPuff for about 7-8 months] He's usually happy to see me and comes up to the glass looking for food. And now he isn't eating either.. I'm soo worried.. Is it possible that they just miss each other? They haven't been apart for the past 3 months at least and they get along REALLY well.

Volume and Frequency of water changes: I usually do a 75% water change every month and a 50% and 25% in between.

Chemical Additives or Media in your tank: I always add the recommended dose of Amquel [1 tsp per 10 gal] when I do a water change and have started adding aquarium salt [1 tablespoon per 5 gal] the past couple water changes also.

Tank inhabitants: Two green spotted puffers and java moss

Recent additions to your tank (living or decoration): I added Natures Ocean Aragonite Sand substrate to the 10gal after PuffPuff got sick and I moved him to the sick tank. And that's when Puffy started freaking out. I think it was because the sand added too much salt even after I washed it.. [The tank used to be almost completely freshwater: some salt added from the crushed coral substrate they had prior to the sand] But I've done another two water changes to lower the salt content [today and yesterday] and it helps for about 15 mins then he gets all weird again.. The salinity is at about 1.012 after two water changes and it was at 1.022 when I first added the sand [day before yesterday]. I only just got a hydrometer yesterday because I was planning on slowly getting my tank to almost marine conditions.

Exposure to chemicals: None

Pictures:
PuffPuff

Puffy


Please let me know if you have any suggestions! Thanks

What sand did you add? Sand shouldn't be salty.

If you think the sand is causing the problems then remove it ASAP.

I'd also suggest more frequent water changes.

In the "hospital" tank do you have sand? - if you don't it could be an indication that the sand is causing a problem.

If you have only recently started adding salt then it could be that too...

EDIT: I've removed the incorrect information - I assumed they were a different variety, apologies.

dipsydoodlenoodle said:

What sand did you add? Sand shouldn't be salty.

If you think the sand is causing the problems then remove it ASAP.

I'd also suggest more frequent water changes.

In the "hospital" tank do you have sand? - if you don't it could be an indication that the sand is causing a problem.

If you have only recently started adding salt then it could be that too...dwarf puffers are freshwater fish (the larger ones are salt water). I suggest you do a big water change to try and remove most of the salt content.

Click to expand...

For the sand I added Natures Ocean Aragonite Sand substrate. I bought it from Petco.

I've been doing daily 25% water changes. Should I change out more water? I'm scared to take out too much of the original water since I just did a 75% water change two days ago..

I don't have sand in the hospital tank, but could sand I bought from Petco that's sold for marine tanks be affecting my puffer so bad?..

And I have green spotted puffers and I thought they were brackish water fish? I know my pea puffers/dwarf puffers are freshwater [they're in my moms tank] but I've been reading that the green spotted puffers should brackish or marine water and that's why I added some salt. And I brought the salinity down even more today by doing another 25% water change with freshwater, so my salinity is about 1.009 now.

I feel bad for my puffys now, I hope the sand I bought them isn't going to affect them.. Otherwise I will probably have to completely empty and redo my tank.. Bummers..

Dipsy please dont give dangerous incorrect info.
GSP's need high end brackish when mature, even marine. Saying this, they can be plunged from fresh to high end bracking with no problems. Salt isnt your issue here.

We need proper ammonia readings. Ive had lots of GSP's, and can almost guarentee that the tank is too small, and you dont have adequate filtration. I had to run 2x fluval 4+ on a 100litre tank, along with two 40% water changes a week.
They are very messy fish.

A sign of ill health is a black belly. The GSP's in your pics look ok to me.

Buy a bigger tank, or risk losing your puffers. Mine were about 6 inches long, and 4 inches thick fully grown. Its an impressive sight, so please dont jeapordise these beautiful fish.