Best fish for taking care of copepods/pests? (Six-line or mandarin maybe?)

[Speedy77]

Hey guys!
I've been searching for a solution to my copepod problem for the past few weeks and cannot decide which fish would be best to get. I currently have a 20g long, with various corals, a cinnamon clown, and a blue sapphire damsel.

Everything was fine until I noticed what looked like small white bugs all over my weaker zoas. From my research I found that in some people's tanks, certain species of copepods will go after weaker zoas if left unchecked. Unfortunately they killed my fire and ice zoas and have moved on to the next weakest group.

I had bought a six-line on sale at Petco, but decided to play it safe and leave it in a hanging no-flow incubator to monitor for the first few nights to make sure it didn't have any obvious signs of disease. I also added a few zoas to the incubator so it could potentially get food from some of the bugs on the zoas. I'm not totally sure what happened next, but something tells me that the six-line aggravated the zoas and they released some palytoxin, because by the next morning the water in the incubator was cloudy and smelly, and the six-line was dead :worried: .

Now I'm looking for another tank-mate to help the same issues in my tank. I've heard good and bad things about the six-line, and after losing the first one am a bit hesitant to add it to the tank. It's great for various pests and easier to feed pellets, but has the rep of becoming a terror over time. I've owned a mandarin before, and love those guys as well. However, their diet doesn't span the number of pests that the six-line's does, and is much harder to introduce to other types of food. I'm aware that there's other types of wrasses that could get the job done, however I like my snails and hermits and know that tank size is an issue.

Considering my tank size as well as the issues in my tank, what might be a good option for me? Any advice is appreciated!

 

[Betta132]

Possum wrasse?

 

[Marshall O]

Possum wrasse?

Agreed. They hunt for pods all day long. They will likely not take care of as many "pests" as would say a Halichoeres, but they should serve your purpose well. I would not recommend a Mandarin as it will very quickly wipe out all pods in a 20 gallon and then potentially starve. A Possum Wrasse will hunt all day, but will still readily accept prepared foods (they love small meaty foods like Mysis).

 

[woodnaquanut]

a hanging no-flow incubator

No flow? That can't be good. Most likely there was not enough oxygen in the container to support all the life in there.

How about trying the next fish in a real QT tank? Flow, filter and heat :thumbsup:

 

[Speedy77]

Awesome sounds good, I'll check it out the possum wrasse!

meant no-flow as one of those hanging plastic things you see people in the pet store use that doesn't allow flow from the tank into the container. It would allow the fish's new tank mates to see the fish and get used to it while acclimating temperature but without sharing water so any potential sickness wouldn't spread. I've used it before without any problem, replacing a few cups of water every few hours while monitoring a fish. It's all I can really do without the space for an isolation tank. I'm assuming the variety of zoas I put in there got upset that they were in a small closed system with the others and got a little biological. Definitely learned from that!

Thanks for the help!

 

[Lucky Lefty]

I'm a noob, but I've never seen a "no-flow" hang on container used in that sort.
Anything I've ever seen hanging in a tank for acclimation purposes has holes in it to allow flow and gas exchange.

I would be wary of your isolation process, or you may lose another fish just as quick.. just a suggestion.

 

[Speedy77]

Sought advice from the LFS, has also worked in the past. The only issue that arose was with the multiple kinds of zoas with the six-line, everything has been fine in the past. I've even treated zoa rocks that had aiptasia on it for several weeks without any issues, it's a great short-term solution to monitor fish for a day or two before introducing them into a tank without sharing water with the larger tank. Normally I wouldn't use it with fish, but was a bit hesitant with the issues I've had with Petco's fish in the past. Most of the time I use it for a few hours to do a slow drip-acclimation and to introduce the fish to other inhabitants without giving them the opportunity to pick on them. Ideally I would love to have an isolation tank but I don't currently have the space. I can see how it could raise some concern, thanks for bringing it up!

 

[MondoBongo]

No flow? That can't be good. Most likely there was not enough oxygen in the container to support all the life in there.

How about trying the next fish in a real QT tank? Flow, filter and heat :thumbsup:

this.

good water movement is critical for gas exchange and everything else. having the zoos and fish in a small container with little to no water movement (not to mention the potential for ammonia build up from waste without access to your biological filtration in your main system) is most likely the reason for their demise.

don't get a mandarin, or any other type of dragonet. that tank is too small to support them long term, and if you can see the pods clearly, chances are that they are amphipods, not copepods, which dragonets are less prone to eat, due to their large size.

next, i would be highly suspicious that the pods you saw on your zoas killed them. barring a subset of isopods, amphipods and copepods are primarily detrivores. if you see them going after a particular coral, chances are it was already on its way out.

i say this from experience as well. i had some red people eater zoas a while back that were not doing well. had been closed up for days, and were dropping polyps. so i watched at night, and found it swarming with large amphipods. i assumed they were the culprit, and yanked the frag out to put it in QT.

turns out, my lights were the issue. i had some bargain LEDs that were complete junk, and were frying some of the more sensitive zoas in my system. after i swapped them out for quality lights, i noticed a HUGE improvement in growth (there actually was growth) in all my corals, and was able to bring the red people eaters back from the brink.

so, all that to say that the old saying holds true: correlation does not necessarily imply causality.

just because the pods are there, doesn't mean they're the ones inflicting the damage.

 

[MondoBongo]

Sought advice from the LFS, has also worked in the past. The only issue that arose was with the multiple kinds of zoas with the six-line, everything has been fine in the past. I've even treated zoa rocks that had aiptasia on it for several weeks without any issues, it's a great short-term solution to monitor fish for a day or two before introducing them into a tank without sharing water with the larger tank. Normally I wouldn't use it with fish, but was a bit hesitant with the issues I've had with Petco's fish in the past. Most of the time I use it for a few hours to do a slow drip-acclimation and to introduce the fish to other inhabitants without giving them the opportunity to pick on them. Ideally I would love to have an isolation tank but I don't currently have the space. I can see how it could raise some concern, thanks for bringing it up!

slow drip acclimation can be a potential killer, poisoning fish with ammonia build up. it is not recommended for most animals.

the only surefire way to prevent disease entering the main system is with a rigid adherence to a well accepted QT protocol. be that tank transfer, prophylactic treatment, isolation and monitoring, etc...

 

[Speedy77]

this.

so, all that to say that the old saying holds true: correlation does not necessarily imply causality.

just because the pods are there, doesn't mean they're the ones inflicting the damage.

Awesome, thanks for the well-explained help! Perhaps I'll try moving the zoas around a bit, maybe that will yield some better results. I've got some zoas that are looking great, but others that don't quite look as happy as they should. My assumption was that it was the pods, but as you mentioned this may not be the case. I may look into the possum wrasse over the next few days and continue to research the best option for my tank. Thanks again!

In regards to the comments on the incubator, I really appreciate the advice as well. Slow drip has worked for me, and I don't really understand all the hate if water is being slowly introduced into the container and slowly taken out; especially considering that overnight shipping from online suppliers would leave a fish in the same water for 12+ hours without significant problems. It was my mistake placing the zoanthids into the incubator with the six-line, but I don't see any serious issue with having just a fish in it, at least for a few hours. I absolutely agree that there are better things I could do to acclimate the fish and can see the fault in the method, I'll be working on that if I choose to add more fish. Thanks again for your help and comments, it definitely helps me work through some of the issues in the tank!

 

[Moort82]

I wouldn't want a timid fish like a possum wrasse in a small tank with a Cinnamon clown and a blue damsel tbh. I think a sixline would be the best fit as they can give as good as they get but please rethink your acclimation process. A no flow tub is likely to have caused the death imo. Sixlines create a mucus cocoon at night and this together with an ammonia build up will have probably caused the demise.

I'm also highly dubious that copepods would do any harm to zoas. If it was white bugs or similar it could well have been aeolid nudibranchs and mandarins are not a natural predator for these (not that I would ever advise one for your system anyway) but sixlines are normally pretty good. Yes they are feisty but given your other fish I think that is no bad thing.

 

[Speedy77]

Sixlines create a mucus cocoon at night and this together with an ammonia build up will have probably caused the demise

This was my thought as well, but I was leaning towards palytoxin due to the 3 types of zoas in the container. When I found the fish, two of the zoas looked upset and one was super big and open, and there were even dead pods and bristleworms on the bottom of the container. This may have been due to either the mucous or the palytoxin, but based on the happy zoa I assumed palytoxin.

Thanks again for all the advice, I think I'm going to set up a QT tank before I buy another questionable fish. I've got a nice incubator that has flow that I used in the past that I'll use to introduce new fish from a LFS that I trust. Thanks again for the help!

 

[snorvich]

Trusting an LFS for quarantine?

:crazy1:

 

[Speedy77]

Hey guys, just wanted to post an update!
Thanks again for all the advice; I ended up asking a LFS about the possum wrasse and the owner was able to pick it up the next day (turns out most places either didn't have them or had never heard of them). He sold it to me as a white banded possum wrasse and gave me $10 off LiveAquaria's price, but when I got home I found out it was in fact a Tanaka's wrasse!

He's doing great and will be introduced into the tank during lights out so he can avoid potentially being picked on by any of his tank mates. I followed the advice here and avoided using the hanging no-flow incubator and instead really checked him out before buying to ensure a smaller chance of any disease and placed him in an incubator with flow so the other fish could get used to his presence without being able to get to him. After about 24 hours in the tank he's looking great! Thanks again for the help and advice.

Here's a picture of how he's doing!