I would recommend a volitan or a miles, which is a slightly smaller version of the volitan. The volitan will get over 8", likely 10-12"; with the miles usually settling just at 8-9". It's really hard to tell the difference and most so called experts don't even get it right, These will take to dead food rather easily and eat enough variety to satisfy their nutritional requirements. You can never be guaranteed if a dwarf or medium bodied lion will take to dead food, and if they do they are usually so selective and difficult to get them eating the right foods. In a more rare situation rather than the rule, you may get one to eat the variety of dead food needed for long term success. For loads of info on keeping lions, click my name and "find all threads". Young small lions need feeding maybe every other day while eventually a couple times a week, overfeeding in the form of feeding too often can be a killer, developing fatty liver disease. Another cause of premature death is Vitamine B1 deficiency due to feeding foods with too much thiaminese; ala krill, old frozen shrimp, and many brands of silversides with the exception of Hikari. These seem to be the foods that most of the smaller species accept, if they accept any at all, that's why they are so difficult to keep long term on a dead only diet. Salmon, mussels, scallops, shrimp with shells, and Hikari silversides will keep a volitan happy for a decade or more. Try to buy fresh and freeze small batches, nutrients degrade and the thiaminese doesn't. Build your rock scape with multiple caves and vertical perching areas and you may be able to keep up to 3 volitan/miles in a 180g. I say "may" because there are always variables, you can not sex these species visually so there is always a chance for male on male aggression.