We received a question via the All About Worms Facebook page from a reader whose bristle worms have died in his aquarium. Actually, the worms didn’t just die, but “simultaneously combusted,” although presumably this can’t be taken too literally, as we don’t see how worms in a fish tank could be consumed by fire. The reader isn’t worried about the worms themselves, but he is concerned if the death of the bristle worms is a bad portent, spelling trouble for the rest of the tank. So, essentially, the reader wants to know what it means when the bristle worms in your aquarium die.
We’ll begin by saying that there is some ambiguity in the reader’s question, but in a sense it is helpful because it gives us the occasion to address this topic from a couple of different angles.
First, the reader could be concerned with what we outline above: that the death of the worms indicates some basic problem with the aquarium’s ecosystem. This is something that is fairly hard to answer because aquariums are varied and complex. There are a number of factors – nitrite and ammonia levels, salinity, chemical elements in the water you add to the tank – that need to be controlled when you are managing an aquarium. Changes to the balance of the tank can lead to problems, and it is sometimes difficult to figure out what is responsible for what. On this particular topic, we found a forum discussion about bristle worms dying, and the conclusion suggests (but doesn’t establish) that high nitrate levels might kill bristle worms. As you might expect, high nitrate levels can negatively impact the overall health of the tank. Elevated levels can stress a fish’s body, making them more susceptible to disease, and nitrates can lead to the growth of undesirable algae. We have no idea what our reader’s precise situation is, so we are simply making the rather obvious point that an imbalance in a tank that causes the death of worms is an imbalance that very well could affect the overall health of the tank.
And this leads us to the second way, or perhaps it’s just a supplementary way, we can interpret our reader’s concern. He could be worried about what impact a lack of bristle worms will have on his aquarium. In other words, can a tank continue to thrive without bristle worms? In a word, yes, and some people will even remove bristle worms from their tanks because they don’t like the worms. (The worms can either be consciously added to the tank, or they will be brought in on something you add to your aquarium, like live rock.) However, most bristle worms are beneficial scavengers that contribute to the overall equilibrium of the tank, so they are generally good to have around, but their absence isn’t necessarily a problem.
Overall, then, it is hard to offer our reader any sort of specific advice because aquariums are unique, and thus have unique problems. In general, the simultaneous death of all your bristle worms seems like cause for concern, so perhaps now is a good time to check the overall health of the tank.