Mr. Saltwater Tank TV Friday AM Quick Tip #117: Should Fish And Clean Up Crew Be The Usual Suspects?


Fish and clean up crew members can be your coral’s friends, or they can be foe.  Here’s what to watch for to make sure the usual suspects aren’t guilty of a coral eating crime.

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Comments for this article (9)

  • Kyle says:

    I have certainly had this problem! I had candy apple polyps kept dissapearing. We had no clue who to blame and it turned out to be the emerald crab in the middle of the night.

  • Matt says:

    Great tip, certainly if you’ve not seen the behaviour before and you will folks. I stopped thinking about it a long time ago until my partner tried her hand at placing some freshly dipped coral. Her immediate thought was that the fish/CUC were trying to eat it as in the quick tip.

    A quick explanation and pointer that its a great time to watch your fish as they’re pretty much in one area for a while rather than darting about the tank … 🙂

  • JasPR says:

    I think Mark is one really smart guy when it comes to keeping marine systems! In fact, he has insights that most fo us take twenty years to get our heads around ( that ” I could have had a V8 moment!”). But on this one, I do get the point (* random foraging is not as deadly as it might first appear) BUT if you spend some time scuba diving in the Pacific or local caribbean/atlantic, coral based fish are constant forages. Prey or diet omnivores ( amino acid sources) as opportunists and grazers. There is no doubt that familiar foods are recognized in a closed captive system and fish become almost obsessed with some specific prey items or dietary additions. But the underlying worry or key to all this is the endless foraging- and in a closed system of even 180 gallons we are talking about 12 square feet of foraging space! Add a few centropygi, a few tangs and an Emp and you have massive ‘accidental’ damage from foraging. To get a sense of this, watch a christmas tree worm pop in and out and get a sense of the pressure on the inverts.
    Recently, a good friend bought a tiny lemon peel angel from a store’s frag tank– looked well behaved and very healthy and active. In 48 hours he had to trap it and send it over to one of my all fish tanks as it had decimated a cluster of polyps and was working another. No such damage was evident in the frag tank at the store he lived in for a week.
    Point is, they are only fish, but they have preferences, personalities and peculiarities. When in doubt, go with the ‘known’ characteristics of a species and take the risk– but don’t be surprised if general foraging takes a toll. For what it is worth, JasPR

  • My fish are hoodlems that like to push the new frags until they fall over so i have to add new frags late at night so the fish don’t notice the new guy…lol Brooklyn Hoods with fins

  • I wonder if newly added corals attract the attention of fish when releasing their defensive toxins. Usually fish ignore them a few days after they’ve been added

  • Chris G says:

    my tanks do this all the time….”FRESH MEAT!!!”

  • Rusty says:

    Amen. Recently had someone bring over some badly damaged lps and sps corals for me to rehab in my tank and my first thought was “I hope my hermit crabs, snails, and fish take care of the algae on these frags and clean up the dead tissue. Day one. Wish granted. All dead tissue has been eaten and healthy tissue left alone. I’ll take it!

  • Gavin says:

    Hi There
    My Deltec apf 600 protein skimmer is not production enough bubbles to cause the bubbles to climb all the way up the throat. I have set the waterlevel as advised but to no avail. What is wrong and what should I likely replace.
    Any idea where I can get the spares from in South Africa?

    Thanks once again

  • Ben says:

    Hey Mark,
    This is a completely unrelated topic, but I need all the help I can get. I want to upgrade my filter to a sump refugium type filter, as my canister (I know, I know, bad but it was fine for almost a year!) isn’t cutting it anymore. I have everything planned out, but I don’t know how to get water OUT of the tank. I want to do a overflow, but I don’t want to drill holes in my active tank. Here are my options, a DIY overflow filter with PVC pipe (don’t really want this, it doesn’t look powerful enough to be by itself) hang on back overflow, or tear down the tank and drill holes in it. (really don’t want to do this one) what do I do? If you have a idea better than these, don’t hesitate to put it down.
    Thanks.

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