Try shade. When I got my prizes hallucinations I wanted them right up front were I could see them. Had them there for years, they grew painstakingly slow and looked liked they were about to die. I threw them behind a rock recently and they are doing great, even though I can barely see them
Stratospher Zoa loves to be more in the shaded area, but the care on them are extremely fragile (hence the big fat price tag that goes along with them). Shade, low flow areas, and target feeding them are your best beat to success.