Your question is not easy to understand, maybe a google translation?
Weather Loaches are very social, a group of at least 6 should be bought, I had 8.
They need a 5-foot tank long term, my group quickly grew from thin ~6cm fish to chunky (as round as my index finger) ~15cm in less than nine months and they should reach somewhere close to 30cm eventually. They might be very docile in the day, but they are very active at night, mine did lap after lap of my 5x2x2.
They are usually greedy eaters, so you need to take care in not choosing any tankmates that are shy at "dinner time." They also need excellent filtration as they get bigger, big fish eat a lot of food and produce a lot of waste!
Weather Loaches are often put in tropical (~25C) tanks, but they do far better in sub-tropical water in a tank without a heater that stays below 22C (I think they are fine down to something like 10C without googling).
Deep soft sand and lots of shady spots will keep them happy in the daytime, where they will burrow with just their heads above the sand.