I have a colony of multis and they are amazing! They can definitely live in a 10 gallon but you will have to thin them out over time, or upgrade to a larger tank in the future. I would start with 6 and let them multiply! They require hard water with a high ph. They prefer sand bc they are diggers and are constantly rearranging their territories. (meaning you don't need plants, as they will just dig them up anyways.) I use aragonite sand, which helps buffer the ph. you can also use a buffering agent in the water. the most important thing they need, apart from their water parameters, are tons of shells! some people say they only need 2-3 shells apiece, but i find that mine prefer lots more. they can be greedy and claim a few each. i have a 20 long with a dozen adults, and we just discovered our very first fry! so it looks like soon i will be adding more shells....the shells in their natural habitat are hard to find, so you can use many other types, as long as the diameter is around 2 in or more, and the opening is large enough to get in. i use large and XL escargot shells (you can get them in fancy grocery stores, or online for cheap) and also whale eye shells. rocks are not necessary, but i have found that even one large rock off to the side is really helpful. My multies hide behind it while I clean the tank. You're right, these guys are HARD to find...I got very lucky and found someone locally who sold me his entire colony. I second Gulfstream and recommend ordering online. Dave's rare fish is in San Antonio so shipping would be cheap to you. I just spoke with them actually and right now they have multies in stock for $8! Usually they can go for as high as $20! I am also planning on breeding and will hopefully have fry to sell in the future, so check back if you want! But it is a good idea to add ALL the shellies you want all at once bc newcomers with be considered outsiders and shellies are very territorial and protective of their colony. (At least that's the case with multis.) These are really fun fish and I can easily spend all day just watching them interact with each other and rearrange the sand. (I like to smooth it out when I clean...it ticks them off, but it's oh so fun for me lol!) Good luck to you!
