20갤런 어항에 물고기를 몇 마리 넣을 수 있나요?

“This isn’t just a glass box—it’s a living, breathing world.” That’s what I always tell my customers, especially when they’re choosing their first aquarium. The conversation often involves tank size, fish species, and how to create harmony in this underwater ecosystem. Today, I’ll share my experience to answer a common question: *How many fish can safely…