Figure 8 Puffer, may have internal parasites?

[ZooPuff]

I have 2 figure 8 puffers, I have had one for about 2 1/2 months and the other for about 2 months. They are in a heavily planted 10 gallon aquarium, just until I get my 55 gallon in August (they love each other, always swim together and never fight except for a little attitude/ nippiness during feeding time, but neither has ever left a mark on the other). The first one I got (Captain Jack Sparrow) is very healthy and happy, the second (Barbosa) is happy and mostly healthy except he is much skinnier and has been since I bought him. Barbosa acts completely normally, constantly greeting me at the glass, eats vigorously, and has normal poo's, I feed them until their bellies are nice and round, but by the next morning he is very skinny again (see picture). I alternate feeding them frozen blood worms and frozen PE Mysis shrimp, along with one pond snail a per day.
Parameters (what I can glean from test strip):
Ammonia: 0
Nitrate: 30 ppm
Nitrite: 0
pH: 7.6
I am concerned about how skinny Barbosa is compared to Captain Jack Sparrow, my first instinct tells me its internal parasites so I am considering soaking their blood worms in Prazipro, but I thought I would get some input first.
Thank you!

[Pufferpunk]

Your nitrate is way too high. My guess is because that is tank overstocked. Even just a single F8, needs a 15g alone. I can't tell if this may be the issue but it wouldn't hurt to treat for IPs.
library/puffers-in-focus/fig8/
library/hospital/internal-parasites-pre ... treatment/

[ZooPuff]

Like I said the tank is only temporary, I live in a dorm right now and don't have the space for anything larger right now, but as soon as I move into my apartment in August I will be getting a 55 or larger. This is the highest I have seen my nitrates, and I suspect its because I have been having issues with my plants. I do 25%-50% water changes one per week, and the puffers are about 1 inch and 1.5 inches right now. I just changed my lighting system so I am hoping that my plants will bounce back and take care of some of the nitrates. In addition it could be an error in reading because I am using test strips, I normally have my LFS test my water but I don't have transportation right now. If you have any suggestions to bring down the nitrates that would be helpful. However I dont think that my nitrates are causing him to be skinny because the other one looks as healthy as can be. I will go ahead with the prazipro treatment (soaking their bloodworms). Thank you for the feedback!

[Pufferpunk]

Larger, more often, WC will help with the nitrate. Is the tank brackish?

[ZooPuff]

Yes, right now I am at about 12 tbls per 10 gallons, I have been slowly increasing salinity since I got them from my LFS. At the store they said they don't usually measure the salt but use "a handful of salt" - this is for all their connected brackish tanks, so I started off with about 1 tbls per gallon.

[Pufferpunk]

You need to be using marine salt to make BW. Get yourself a hydrometer & measure properly. Be sure to read the articles I linked.

[ZooPuff]

I do, and I just recently ordered a refractometer, I was saving up for it. And my mistake I meant to say that I started off at 1 tbls per 5 gallons I believe it was. I actually read all of that stuff (and much more) before I got these guys. I am very concerned with proper care of my animals as I want to be a vet, however I can't always buy the things I need right away, but I do the best I can under my broke college student situation.

[Pufferpunk]

Then why did you purchase fish for a tank that is too small, especially 2 of them?

[ZooPuff]

because it is temporary. this is not their final home. as ive said twice before. and I wanted to buy them as juveniles so that they would get along better. they tend to fight more with greater age differences especially if one is older and has been alone for a few months. in addition I dont appreciate your condescending attitude. I came on here looking for an answer about my puffers sunken belly. as I said before they are both in perfect condition aside from the puffer being skinny. and I purchased him in that condition. I recognize the situation is not ideal and thats why it is temporary until I have the space to get them a tank much larger then they actually require.