Ok so I'll try to answer most of these let me know if I miss some or you have more questions.
Also I'm not trying to desurage you and I certainly hope you go ahead with this nano project but perhaps in a different way.
For the most part the comman jawfish you will find in most LFS are spotted jawfish or various types of pearly jawfish. These guys tend to get pretty big and probably wouldn't do great in a 10 gallon.
There are some jawfish that do ok in nano tanks but they aren't very comman and usually rather expensive sometimes in 100$ or so range.
Another probelm with jawfish is they require a substrate that is both the right type and depth for them to build a burrow in where they will live. The best substrate for this is 2 parts sand 1 part fine crushed coral gravel mixed well and spread out at a depth of about 4 inches.
No here's where the probelm comes in when using a smaller tank like a 10 gallon with a sand bed that deep it takes up a lot of the tank and then you don't have much water volume which will make it even harder to keep an already small tank stable.
Jawfish tend to be very picky with food and most people have to get them eating on live foods such as brine shrimp and other shrimp then try to wean them on to frozen foods.
Most jawfish are reef safe so they won't pick on crabs or coral so that is good.
Another downside to these fish is they tend to be very skittish and come out of there hole only at night so you don't get to see them often.
They won't handle a lower salinity because they are a full on saltwater fish so they require ocean salt levels rather then brackish levels.
I know a lot of this is negative and I hate to sound that way but there is a lot of special care for these fish and most people don't keep them for that reason. Plus I'd rather tell you all this now then make you find out the hard way.
My honest suggestion is in that 10 gallon get a goby of some type they look a lot like a jawfish but they don't require a deep sand bed most stay small such as neon gobies and clown gobies. They are very easy to feed and most are completely reef safe.
They are also much more forgiving of water standards not to say you shouldn't keep up with regular water changes and top offs of freshwater to keep salinity stable but they are much less fragile then jawfish are. You can also keep shrimp with them which in a 10 gallon a colony of shrimp are awesome to watch and make a great clean up crew.
If you do a google search of gobies that are ok in a nano tank you will find tons and I encourage you to do so if nothing else just to see some of the cool fish there are
Anyways hope to see you do this nano tank and whatever you choose to go with good luck!
for reading.
