The necessity of a CUC?

[Treefer32]

I know this is an extremely controversial post. I've been running a 340 gallon mixed reef for about 2 years now. Prior to this I ran a 220 and a 125. I've battled all types of hair algae briopsis and so much more over the years.

My Tank is algae free. Currently has a Cyano outbreak that is from a nitrate spike but I'll have that cleaned up within a couple months. My CUC has been very minimalistic. I've had 3-4 mexican turbo snails for most of the two years. I don't honestly know where they came from, I never purchased them, but, may have come in on a couple pieces of rock I got from a friends tank and/or hitchikers on coral rocks from others. The only CUC I intentionally bought was a few Nessarious snails. (Maybe 10 or so). Which, every now and then I see an antenna sticking up that tells me they're somewhere in the sand or one might sneak up on the glass at night here and there, but, it's very rare.

I think the nitrate spike was from the death of 3 turbo snails. My Dragon Wrasse got more and more agressive with them, kept constantly flipping them over. I couldn't keep up with him in terms of flipping them back and I think they died of starvation.

So, that said, I have no intentional CUC other than the nassarious snails I may or may not still have. However, my rocks have grown their own filters. I have yellow and clear sponge growing all over the place. The tank is filled with tubes sticking out of the rocks everywhere. I now have a small colony of asterina starfish growing on my glass. None of these were purchased nor intentional.

My choice for CUC is to let nature decide what's best to filter my reef and stop feeding my dragon wrasse snails. My Dragon wrasse constantly stirs the sand and anything he misses hopefully the nassarious snails get.

I know many would disagree with no CUC, but, given I have a couple fish agressive towards CUCs do others go without CUC and have success?

P.s. I run an oversized skimmer, a algae turf scrubber, purigen with a Nu-clear 25 micron cannister filter for polishing the water, and do 2 water changes a week at 12% per water change.

So, far this has worked for me, I did have an outbreak of briopsis that took about 6 months to win but it's permanently gone and nothing coming back in it's place.

to CUC or not to CUC?

 

[Timfish]

I've found most of what is offered as CUC die off in less than a year's time. Personally I like a couple of the larger brittle/serpent starsand ac couple royal/tusedo urchins per 100 gallons and a few of the larger hermits like Blue Knee or White Strip hermit crabs.

 

[Bfragale]

I like the urchant- maybe a Sand shifting star.

I’ve had more issues with large crabs. Small crabs seem to be better in regards to knocking things over and disturbing corals. But the large ones are little bull dozers lol.

Some large snails also knock things over. But have had good luck with snails except them always slowly dwindle down in numbers..

Many rely on bristle worms and other natural cuc.

I think if it’s working for you then keep at it!

Good topic- I’m following to see others responses.

 

[Reef.]

I wouldn’t have thought 3 snails dieing in a 340g would have caused a nitrate pike.

I tend to agree though, fish are way better algae eaters, I do enjoy watching snails etc they add a lot to a tank, so worth having a few just for that reason.

 

[Difrano]

Yes and No:

Yes: you need CUC in your tank, some snails, worms, urchin, conchs, crabs etc... just a few of them, they add biodiversity and help with algae and most important detritus, I love amphipods they are the best CUC I ever had, they keep detritus at bay and at the same time they are food for your fish.

No: You don't need the CUC packages that some vendors sell online, you don't need 300 snails, 400 hermits, 100 bristle stars in a new tank, not even a old tank.

 

[Treefer32]

Awesome. I do have a conch from a friend's tear down as well. I've thought several times that he's dead. But, I saw him moving yesterday. So, he's alive. He gets free rides across my tank from my Dragon Wrasse. If I got crabs, they would need to be larger crabs otherwise my Dragon wrasse would just move them around. He's got a large pile of rocks and debris piled at his house. I've had to "nail" down every coral I have. If the frag plug is loose at all, the Dragon wrasse finds it and drops it in his pile of "Here marks my house".

He gets mad at my conch for continuously moving around the tank, but, he just picks it up and drops it in a new spot. Doesn't actually eat it. . . I'm not sure what his goal is. He just wants things in a certain spot....

I also agree, most snails do die off within a year or so. I did have tiny nerites once that reproduced like mad I was able to sell them in the hundreds to local reefers. But they were so tiny that it's really a pointless snail in a larger tank. I agree with something eating detritus. I have bought pods a couple times and with the ATS even with cleaning it every week, my tank has hundreds of pods floating in the water column. I believe it's molts. So, I'm hoping maybe part of the unseen CUC are massive numbers of pods.

 

[Lasse]

Do you have Tangs?

Sincerely Lasse

 

[ca1ore]

I have no intentional CUC

This is the key point. Don't define CUC as just the stuff you buy; define it as ALL the organisms that live in your tank (including the herbivorous fish). Heck, fish are the CUC for the food you add LOL. I occasionally add a bunch of hermit crabs, not because I need them for the CUC but because I think they are cool to watch. The unintentional CUC does all the heavy lifting.

 

[Miller535]

I personally think CUC are needed. Not nearly what the vendor sites tell you. Their recommendations of 1 critter per gallon is absolute garbage. There are options for things like urchins that are going to be totally left alone and live a decent amount of time. 1 urchin will do more then dozens of any snail. I also agree with others that a clean up crew is anything that eats uneaten waste including fish. I personally find sponges every where and tubes and a lot of those things unsightly. A clean up crew as long as you were not overfeeding could have helped prevent all of the algae outbreaks yout have had to (post the ugly stage).

 

[Miller535]

To give an example I have a 125 gallon tank. I have 1 rose urchin and 1 pincushion, maybe 4 turbo snails, 2 brittle serpents, and 4 conchs. And I have no need for any more. And I have no crabs of any kind.

I also consider pods a important part of a cuc.

 

[Tired]

If you don't remove algae, you will encounter problems. You could theoretically go without a cleanup crew if you put a ton of effort into manually removing the algae, but I don't know why you would. If you don't do that, you need a cleanup crew to eat algae, but what you need to do that varies depending on the tank. An urchin will eat lots of algae, that's a big contributor for some people.

 

[nikki7181]

Awesome. I do have a conch from a friend's tear down as well. I've thought several times that he's dead. But, I saw him moving yesterday. So, he's alive. He gets free rides across my tank from my Dragon Wrasse. If I got crabs, they would need to be larger crabs otherwise my Dragon wrasse would just move them around. He's got a large pile of rocks and debris piled at his house. I've had to "nail" down every coral I have. If the frag plug is loose at all, the Dragon wrasse finds it and drops it in his pile of "Here marks my house".

He gets mad at my conch for continuously moving around the tank, but, he just picks it up and drops it in a new spot. Doesn't actually eat it. . . I'm not sure what his goal is. He just wants things in a certain spot....

I also agree, most snails do die off within a year or so. I did have tiny nerites once that reproduced like mad I was able to sell them in the hundreds to local reefers. But they were so tiny that it's really a pointless snail in a larger tank. I agree with something eating detritus. I have bought pods a couple times and with the ATS even with cleaning it every week, my tank has hundreds of pods floating in the water column. I believe it's molts. So, I'm hoping maybe part of the unseen CUC are massive numbers of pods.

Your dragon wrasse is the opposite of my watchman goby. Mine will pick up any snail/crab/ect and move them away from his house. He says "stay off my turf"

 

[nikki7181]

This is the key point. Don't define CUC as just the stuff you buy; define it as ALL the organisms that live in your tank (including the herbivorous fish). Heck, fish are the CUC for the food you add LOL. I occasionally add a bunch of hermit crabs, not because I need them for the CUC but because I think they are cool to watch. The unintentional CUC does all the heavy lifting.

I enjoy watching my CUC as much as my fish.

 

[Treefer32]

If you don't remove algae, you will encounter problems. You could theoretically go without a cleanup crew if you put a ton of effort into manually removing the algae, but I don't know why you would. If you don't do that, you need a cleanup crew to eat algae, but what you need to do that varies depending on the tank. An urchin will eat lots of algae, that's a big contributor for some people.

I know that's what I was thinking too. But, given my tank is algae free now (other than a few spots of Cyano which are dwindling), I was trying to be forward thinking and see if a CUC helps with old tank syndrome that I've been hearing about. Tanks 3+ year old having nutrient issues. Mine's finally clean and without a CUC and seeming to stay that way. The right combination of filtration, sand, rocks, fish, etc seem to be doing it. I have no issues at the moment, other than the glass filling in with algae within 2 -3 days. I've never had luck with snails keeping the glass clean. Maybe if I had 500 of them they would help, but it's a lot of glass.....

 

[Lasse]

But if you have Tangs - when you have CUC - CUC can be fish too - everything living that help you to clean up your aquarium is CUC - IMO.

Sincerely Lasse

 

[Tired]

For the glass, just use one of those little magnet scrubbers. Easier than trying to get snails to keep it spotless. Too bad they can't be programmed like little roombas.

 

[CelestEel]

CUC can be fish too

I was just about to say that! CUC doesn't only consist of snails and hermits. My fish eat more algae than my snails do. The only advantage snails and hermits have over fish is that they can usually get to algae that is right up against a coral or down in between rocks that fish can't get to. But other than that the fish do a way better job.

 

[stanlalee]

If you can keep a clean up crew in an established reef they aren't cleaning anything, you are feeding them and they are just inhabitants. There is no algae or abundance of uneaten food in a well maintained reef over 6 months old.

 

[Tired]

I would be... pretty skeptical of that. If that's correct, all the cleanup crew could be removed from a well maintained 7-month-old reef, and there would be no increased algae in response. I can't imagine that's true.

Also, a 6 month old reef started with ocean rock, one started with "live" rock that was just in a bin at the LFS for awhile, and one started with dry rock are going to be at vastly different stages of maturity.

 

[flampton]

For the glass, just use one of those little magnet scrubbers. Easier than trying to get snails to keep it spotless. Too bad they can't be programmed like little roombas.

Some company did that! I forget the name of it though. I think robosnail. No idea if it works as advertised