Throughout the last month, it seems that every morning I wake up or every afternoon I come home from work, I am mourning yet another death in the house. There is a killer in my house, and the worst part about this killer isn’t even that deaths are occurring. The worst part is that the killer is invisible. Invisibility has proven to be even more deadly than I was prepared for. You see, I recently added an aquarium to my dining room, and while it has been a lovely peaceful addition to the house, my fish keep dying. That is a problem.

Before I actually set up this new aquarium, I spent months researching and reading and planning for it. I stalked YouTubers that have successful channels regarding their aquariums, fish, and aquascapes. I read website after website after website, and I even started purchasing Practical Fishkeeping magazine to rummage through its many helpful articles. I knew exactly what I wanted my tank to look like, which fish I would keep in it, and which plants I would grow in it. Lastly, yet most importantly, I made sure to get my facts straight when it came to actually starting a new tank. Unfortunately, keeping fish is not as easy as it seems. A quick way to waste all of your money would be to fill it up, dump in some fish, and let it go. In order for fish to thrive in an aquarium environment, a few things have to be in order.

Let me explain. To begin, the tap water that we regularly drink and use around the house has added chemicals in it that are deadly to fish. Tap water that is added to an aquarium has to be treated every time new water is added in order for the fish to live in it. This is only the beginning; because once the tap water is treated, more harmful things begin happening in the water. To keep it short, because I’m blabbing about fish water, the uneaten food left in the tank and the waste that builds up after the fish eat the food infect the water with ammonia. Ammonia kills fish. Rather quickly. That ammonia has to be converted into nitrite, which is also deadly to fish, and then that nitrite has to be converted into nitrate, which is less harmful to fish, and then that nitrate has to be diluted every so often when the tank water is changed. Tired yet? I probably have just persuaded you NOT to set up a new fish tank. I have a point though. All of what I just described happens without being seen. That means that while my tank water may look crystal clear, it could actually be polluted with a deadly invisible killer. The only way to know if this deadly process is kept at bay is to frequently test the water to ensure that it is healthy for the fish. Even then, bacteria can still creep in and slowly kill off the fish. Naturally, this reminds me of Jesus.

Our hearts are also polluted with an invisible killer. Sin. One downside to knowing Jesus on this side of heaven, is that our nasty sinful hearts remain intact for the rest of our lives on Earth. Jesus may have already won the victory over our sinful hearts, but unfortunately, that does not relieve us of the need to continually check our hearts. As I think about the way I have to frequently test my aquarium water, I am reminded of the Psalmist.

Search me, O God, and know my heart! 

Try me and know my thoughts! 

And see if there be any grievous way in me, 

And lead me in the way everlasting!

Psalm 139:23-24

In the same way that my aquarium water looks crystal clear and all seems to be well, so too can our lives look in order and that all is well. I literally cannot afford to let my aquarium water go unchecked because with each fish death, my pennies die. Even more so, as Christians, we cannot afford to allow our hearts to go unchecked when there is a devil that “prowls around like a roaring lion, seeking someone to devour” (1 Peter 5:8). I think the Psalmist gets it right when he asks God to search his heart and thoughts for any grievous way. It is often the invisible sin that proves to be more deadly to us than the “visible.”

Early on in my walk with Jesus, I was blessed to be surrounded by incredible leaders that taught me foundational lessons in my new journey. I learned the value of guarding my heart and protecting my heart from unnecessary evils in my life. I learned to get rid of what was of no benefit and to censor what I allowed myself to see and hear. I learned what was dangerous for my heart and how to protect myself from it. Years later, many of “these things” are either no longer a part of my life or remain heavily guarded and protected. They are no longer areas of sin in my life because I made myself so aware of them that I could see the sin coming. To this day, the greatest sin, if I had to name one of many, to ever plague my life was one that I never saw coming.

The book of James leaves us a valuable reminder of the way in which the devil seeks to devour us.

But each person is tempted when he is lured and enticed by his own desire. The desire when it has conceived gives birth to sin, and sin when it is fully grown brings forth death.

James 1:14-15

Sin begins in the dark places of our hearts. The places that we often forget to look. There, in the murky pits of our sinful hearts, it festers and grows and builds, and so often this occurs inside of us even when we are fighting to keep sin away on the outside. It is invisible to us and those we come in contact with, and the longer it is left unchecked, the more deadly it becomes. When left unchecked, this is the sin that knocks us off of our feet and destroys lives. I have this theory that rarely does a committed follower of Jesus suddenly jump off the cliff. They just don’t see the sin until it has already done the work. What begins as a small seed of bitterness, jealousy, anger, or envy (and the list continues) can grow to become a deadly killer. We must remember to check our hearts.

Every week, sometimes several times in a week, I test my aquarium water with special water testing fish things that I don’t understand. All I have to understand is that the test turns the water colorful, and I use the provided color chart to compare my water to. When I see the wrong color, I have some changes to make. When Jesus won the victory over our hearts, it was done. That victory is ours and He presents us holy and blameless before God. But we would do well to remember that the battle is not yet over. We must learn to check our hearts, even when it seems that things are crystal clear, so that God can reveal the places in our hearts that need a few changes and that we do not see. If we would make a habit of checking our hearts for the tiny seeds of sin, perhaps we would be saved from the more deadly effects that sin has on our lives.

At the end of the day, even though my fish keep dying, I am thankful that somehow God can use a fish tank to draw my eyes to Him.