Yes, if you want to go through a dozen or more fish trying to figure it out. That's what I did.
Over the past few months I've learned a great deal about tropical fish. Goldfish, it turns out, don't have a stomach so they just eat and poop non-stop. Some fish feed on the top, some on the bottom. Allege is food for snails, but mostly on the glass and structures. They don't eat the junk on the bottom because it's not allege. Other fish and critters eat that 'stuff' on the bottom but you probably also need a special vacuum to keep the gravel (also called substrate) clean. Oh, and there's bacteria that's really important for the survival and happiness of the fish. Too many fish means that their waste can quickly become toxic. Too much food is unhealthy for the water and too little food is, well, starvation for the fish. Some fish are really communal while others will eat whatever will fit in his or her mouth (including the tail of a green cory catfish). What I find really interesting is the type of fish that must have other similar fish with them. If they don't have enough buddies they are not only lonely, they just give up and die.
In a mere 3 gallons, I've got a complex ecosystem. Fish that find food on the surface. A fish that eats on the bottom. Shrimp that clean the substrate and snails that clean the glass and broken ship. I have to do partial water changes and there are special pellets in my filter that somehow help the good bacteria grow. And I've had to make many adjustments along the way. Aggressive or messy fish have been evicted. I've added shrimp and snails for the helpful jobs they do. Fish selection became a serious process beyond, "hey, that's a cool looking fish." In order for my community of tropical fish and critters to function in a healthy way, there has to be some balance.
You shouldn't have an entire tank of guppies or snails or catfish. They each of a function that benefits the community. It's a lot like the body that Paul talks about in 1 Corinthians 12. The entire body can't just be an eye. There must by many parts working in harmony. Every part serves a different function and in order to have health, every part is necessary. Community requires diversity and balance.
As I'm working with a core team in preparation to plant a church, I'm seeing how much the church is like a fish tank; but unlike the life in fish tank, the Lord's Church offers grace and Jesus can bring about change. When you have an aggressive person that chomps another person's tail off, you have a problem. But rather than flushing the aggressor down the toilet, we can work together and extend grace while Jesus changes the very nature and hearts of those of us in the tank. Over time, as we seek to live like Christ, we will find greater harmony and healthy spiritual growth in our community. And hopefully we'll find something amazing.
* Photo of clown fish is in the public domain.