Stocking For A 180 Gallon

[justasking]

Hello all! I currently have a 220 gallon outdoor pond. However, my landscaper made an error when creating it so I cannot fill it all the way. As a result, it's actually filled with approx 180 gallons of water. There is much less swimming space than a "traditional" 180 gallon tank since I have a large pump and bio filter as well as a small pond heater and several submerged and/or potted plants. I currently house 3 tinfoil barbs, 6 danios/glofish and 3 albino bristlenose plecos in the pond. I'm wanting to add a few more fish. The tinfoils inhabit the bottom of the pond and the danios swim at the top. I want to get some midlevel fish and am considering either 4 roseline sharks or 5 tiger barbs. I'm just wondering what appropriate stocking levels would be once the tinfoils get full size (15 inches). Would I even be okay to get the roselines and the tiger barbs?