Hi. I’m very New in Keeping fish# tropical fish# diseases related to fish (dealing with human eye diseases on daily bases). Got 100 l tank 6 weeks ago, followed advise on cycling for 2 weeks. Checked water for everything (before introducing fish). Got 2 Molly’s, 2 platies, 2 black skirt tetras (as was advised by local fish supplier). After 25% water exchange, then in few days cleaning filter... checking water parameters.... I introduced 3 more black skirt tetras. After 1 week they developed Ich (I didn’t quarantine fish....as I thought respectable places sell healthy fish). Started treatment with Love fish (White spot& Parasite)....10 ml. Seemed in few days Tetras looked much more better. In 4 days repeated treatment. As I don’t know what to expect.....little bit concerned about 1 tetra, as It has large white “spot” on dorsal fin. I’m very new to fish. Find it very , very interesting! Thanks for forum...lots of info.