considering changing a semi reef tank to a super populated fish only

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james123

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Dec 23, 2008
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so i have a 125 gallon tank that i have had for a little over a year, and i got the idea that i would like to have it super populated with schooling fish. i have 3 tangs in there now, and a few green chromis, but I would like to have TONS of damsels, etc. right now i have about 150 lbs of live rock and a 55 gallon sump. i have a reef octopus extreme 200 skimmer.

so my quesitons are:
How many fish could i reasonably put in a 125?
Do i need all of that live rock, or could i get rid of some of it to have more room for fish?
What about inverts for a Clean up crew? Are they necessary?
What about lighting? I have MH and T5 lighting now, but is it necessary?

would someone with some fish only experience help me out?
 

greech

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May 13, 2009
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so i have a 125 gallon tank that i have had for a little over a year, and i got the idea that i would like to have it super populated with schooling fish. i have 3 tangs in there now, and a few green chromis, but I would like to have TONS of damsels, etc. right now i have about 150 lbs of live rock and a 55 gallon sump. i have a reef octopus extreme 200 skimmer.

so my quesitons are:
How many fish could i reasonably put in a 125?
Do i need all of that live rock, or could i get rid of some of it to have more room for fish?
What about inverts for a Clean up crew? Are they necessary?
What about lighting? I have MH and T5 lighting now, but is it necessary?

would someone with some fish only experience help me out?
Don't have any marine FO experience (only my reef) but FWIW...

1. Depends on size of the fish but if you are talking mostly damsels along with the 3 tangs, I would say 15 to 20 total. If you have a good skimmer and you are on top of the tank you may be able to squeeze in a few more. If you're not stuck on damsels maybe consider some Anthias? The Bartletts might be a good option. Not quite as aggressive.
2. If you're going to max out the bioload on the tank you're probably going to want the rock. If you have a sump and you have room in it just put the extra rock there. I think you could lose 25 to 30 lbs though if you had to.
3. Again, your increasing the bioload so the amount of food and waste is going to increase as well. If you are diligent about cleaning your tank then a scaled down CUC may be ok but I wouldn't have a SW tank without at least some detrivores and grazers. Why do you not want a CUC? You didn't mention any fish that would eat snails, etc.
4. If you are removing corals and any other photosynthetic animals then no you do not need that kind of lighting. Any light will do for a FOWLR.
 

james123

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Dec 23, 2008
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Greech thanks for the feedback...in answer to your question, i don't necessarily not want a clean up crew, but i'm wondering how places like restaraunts and stuff have these tanks with loads of fish and only a couple pieces of fake coral, no clean up crew, and no live rock at all...what kind of filtration do they use? i guess they're hiding a sump that's as big as the tank itself that we can't see...
 

greech

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May 13, 2009
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Yes, those tanks typically have good size wet dry filters under the hood and they also are maintained by someone other than the restraunt owners/employees. They may also not be as healthy as they appear. A SW tank can certainly be done without LR but hosestly I don't know why anyone would. In addition, to be a highly efficient bilogical filter the rock looks natural and provides lots of holes for the fish (which you will want BTW if you load up a tank full of aggressive damsels).
 
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Khemul

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Oct 14, 2010
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How many fish could i reasonably put in a 125?
Depends on the fish. Damselfish range in size quite a bit. A school of Sergent Majors for instance will be much smaller then a group of Talbots. The main problem you are gonna run into is aggression, so research and know exactly what damsels you get. Even then you may find it difficult to keep a large group alive long-term. I'd suggest Amblyglyphidodon species. They are medium sized and they school and are pretty calm as far as damsels go. Talbots are pretty peaceful too, but not sure if they'll school. You could do more Chromis' and have a rather large school of those, but the experience I've heard with them is they almost always pick each other off over time.
Do i need all of that live rock, or could i get rid of some of it to have more room for fish?
Again, depends on the fish. Some types of damsels will prefer the rockwork, others the open space. Find out what types you want to keep and them you can base the rock around them. Most likely you will be able to get rid of at least some of it, since that is a bit of rock for FOWLR.

One tip on rock removal since I saw in another thread that you have a Starry Blenny. If you remove any rock, make sure you know where the blenny is. They like to hang out on/in rocks. I killed one a little while back by not realizing that the blenny had ducked into his favorite hiding place (which happened to be a rock that was temporarily removed). Even though he had been chased away from the spot multiple times as other rocks were removed in the area to prevent such an event, it still happened. They can be tricky to deal with when it comes to rock removal.

What about inverts for a Clean up crew? Are they necessary?
They aren't necessary for any tank. You don't seem to have anything that would make their life difficult, so if you like them keep/add them. Otherwise nothing really says they are necessary, just helpful.
What about lighting? I have MH and T5 lighting now, but is it necessary?
As greech said, if you don't have corals or anemones then those lights won't be needed. Keep in mind you may lose a bit of coralline encrustation (if you have it) when/if you cut back the lights.
 
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SubRosa

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Jul 3, 2009
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A perfect set up to utilize the advantages of biopellets without having to worry about the potential negative effect of nutrient depletion.
 
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