I have too many bristle worms. I didn’t mind them initially but they’ve gotten out of control, in every bit of sand and every rock crevice. They aren’t harming any of my tank inhabitants as far as I can tell, but I do get a couple painful stings that last a few days every time I work in my tank touching rockwork, fragging coral, cleaning sand, etc, which is getting old. Plus they just seem out of balance.
I’m well aware that they are considered a normal part of the clean up crew, and I’m also well aware that the general thought is that you don’t get plague proportions like I have unless you overfeed. I don’t think I overfeed, but I’m not stingy either. I don’t have any issues with nitrate/phosphate/algae.
So anyway I’ve been looking for ways to thin their numbers, including traps. All of the commercial traps for sale get basically bad reviews. I did find someone in UK 3-D printing traps (TT Gadgets) that gets good reviews, but he told me he is closing up shop. I’ve seen the common DIY traps out there, but none of them really piqued my interest.
If I want to outsmart these polychaete worms, I figure I have to think like a worm. Starting from apparent bristle worm preferences, I’ve noticed the following:
1. They mostly like dark places, and if they come out into the light they go back into the dark quickly.
2. They like rock crevices, being under the sand, and generally don’t want to stay exposed in the open.
3. They are attracted by smell to food, especially meaty food.
4. They are very flexible and can squeeze through very tight spaces.
5. They are fast when they want to be, so literally catching them before they can bolt into a crevice isn’t very effective.
Most of the commercial traps are made of a clear or translucent plastic material that lets light in and also doesn’t have any crevices inside, violating #1 and #2. So it’s no wonder that they just crawl out again after they explore/feed. Also the commercial traps have the holes arranged in a way that gives you the feeling that the worms can enter but not exit, like traps for larger animals have. These worms are so flexible I just don’t think this is legit. Rather than trying (futilely) to make it so that they can’t leave, I’d rather make it so that they don’t want to leave.
The 3-D printed trap mentioned above has the advantage of being opaque material so its dark inside, and also they load the trap with rocks, which gives the feeling of lots of crevices. My guess is that it is these 2 factors that make it more effective than the other options out there.
So with all this in mind, I made my own DIY trap. I used:
- An empty opaque plastic fish food container with lid
- Reef-safe small rocks (I used extra-coarse ARM calcium reactor media) to give the feeling of rock crevices inside
- A small scalpel for making entry holes
- An old intake strainer from a dead power head to hold food
- Some frag putty (I used Tunze CoralGum) to attach the strainer to the lid, can be removed to place food
I made the entry holes around the base of the container, near sand level and far from the food, with the flaps pointing inwards in case that matters to make it easier to get in vs out. The holes don’t have to be very large, the worms are quite capable of squeezing through.
So far the trap has been quite successful, initially trapping 30+ worms when used at night, placed in the sand next to rockscape. Surprisingly, I’m able to trap about the same number when I leave the trap out during the daylight hours even though I don’t see the worms. I’ve been using frozen mysis and some fish pellets, but probably anything meaty would work.
The hardened putty is superglued to the top lid, allows me to remove the cage to fill with food.
Filled with rocks and ready to place
Night catch:
Day catch:
I’m well aware that they are considered a normal part of the clean up crew, and I’m also well aware that the general thought is that you don’t get plague proportions like I have unless you overfeed. I don’t think I overfeed, but I’m not stingy either. I don’t have any issues with nitrate/phosphate/algae.
So anyway I’ve been looking for ways to thin their numbers, including traps. All of the commercial traps for sale get basically bad reviews. I did find someone in UK 3-D printing traps (TT Gadgets) that gets good reviews, but he told me he is closing up shop. I’ve seen the common DIY traps out there, but none of them really piqued my interest.
If I want to outsmart these polychaete worms, I figure I have to think like a worm. Starting from apparent bristle worm preferences, I’ve noticed the following:
1. They mostly like dark places, and if they come out into the light they go back into the dark quickly.
2. They like rock crevices, being under the sand, and generally don’t want to stay exposed in the open.
3. They are attracted by smell to food, especially meaty food.
4. They are very flexible and can squeeze through very tight spaces.
5. They are fast when they want to be, so literally catching them before they can bolt into a crevice isn’t very effective.
Most of the commercial traps are made of a clear or translucent plastic material that lets light in and also doesn’t have any crevices inside, violating #1 and #2. So it’s no wonder that they just crawl out again after they explore/feed. Also the commercial traps have the holes arranged in a way that gives you the feeling that the worms can enter but not exit, like traps for larger animals have. These worms are so flexible I just don’t think this is legit. Rather than trying (futilely) to make it so that they can’t leave, I’d rather make it so that they don’t want to leave.
The 3-D printed trap mentioned above has the advantage of being opaque material so its dark inside, and also they load the trap with rocks, which gives the feeling of lots of crevices. My guess is that it is these 2 factors that make it more effective than the other options out there.
So with all this in mind, I made my own DIY trap. I used:
- An empty opaque plastic fish food container with lid
- Reef-safe small rocks (I used extra-coarse ARM calcium reactor media) to give the feeling of rock crevices inside
- A small scalpel for making entry holes
- An old intake strainer from a dead power head to hold food
- Some frag putty (I used Tunze CoralGum) to attach the strainer to the lid, can be removed to place food
I made the entry holes around the base of the container, near sand level and far from the food, with the flaps pointing inwards in case that matters to make it easier to get in vs out. The holes don’t have to be very large, the worms are quite capable of squeezing through.
So far the trap has been quite successful, initially trapping 30+ worms when used at night, placed in the sand next to rockscape. Surprisingly, I’m able to trap about the same number when I leave the trap out during the daylight hours even though I don’t see the worms. I’ve been using frozen mysis and some fish pellets, but probably anything meaty would work.
The hardened putty is superglued to the top lid, allows me to remove the cage to fill with food.
Filled with rocks and ready to place
Night catch:
Day catch:
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