When choosing individuals, attention should be paid to their activity and the condition of their skin. A healthy fish should exhibit natural behavior: actively moving across surfaces, scraping off growths, or firmly adhering to glass and stones. Avoid specimens with visible fin damage, ulcers, film, or an unnaturally swollen abdomen. — Examine the belly: in a healthy individual, it should be flat, not sunken, which may indicate emaciation. — Check the reaction: the fish should react quickly to approach and try to hide or fix itself on a surface. — Ensure there are no signs of stress, such as pale coloration or rapid breathing, which are often observed under poor keeping conditions in retail aquariums.