Fish to gallon ratio?

Sep 26, 2006
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New Jersey
#2
well most people say around 1" of fish=10g but IMO if you have plenty of LR and good filtration (LR,skimmer, etc) you could have anywhere from 20-25" of fish but you gotta be careful as that's a pretty huge bio load
Like i have a 20g with a 10g sump and i've got 6-7" of fish (2 damsels and 3 cromis) now if you went by that 1" of fish per 10g i would need a 70g to keep 5 small fish! Just my $0.02
Nick
 

aresgod

Superstar Fish
Jan 14, 2004
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#4
there is no set easy rule for salt water, as others have mentioned fish vary in eating methods, and inches can be measured in any number of ways...While a good protein skimmer and Biological filtration certainly are a must, they are not necessarily enough to justify over stocking. The size and frequency of your water changes also largely affects what you can keep.

For example, I tend to understock and I keep only two clowns and a goby in my 40 gallon, and I would hesitate to add another fish. But to each his own.
 

TheFool

Large Fish
Apr 19, 2006
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#5
Big fish or little fish? what shapè? , what filtration do you do, how many water changes. This is not a good question to asnwer as there are just too many variables - temperature, salinity and a mass of other things affect this.
Inches really don't work as my purple tang is about 5 inches long, and the size of a small plate - how does that compare to 5 one inch damsels? Weight is better ,,but it's is still very difficult to say
 

Joe Fish

Superstar Fish
Apr 21, 2006
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#7
I keep 7 fish in my 55 and they are fine. Then again I keep 2 smaller clown, goby, blenny, coral beauty, firefish, and a mandarin.

If you water params stay in check then your good. A very important param would be dissolved oxygen.
 

Lorna

Elite Fish
Mar 3, 2005
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#8
Also, some fish have larger personal space than others.......sounds funny but it is true....some fish require more room and space due to territorial issues or are active swimmers and if crowded will cause undue stress and lead to diseases such as ich etc. 7 small fish such as Joe Fish has take up little room are not active swimmers and when coupled with good husbandry pose no problem in a 55g. On the other hand if you were to have say a lion fish/puffer or active swimmers such as a tang (though I think 55g is too small for any tang) you would need to keep the number to a bare minimum......
 

CoolWaters

Superstar Fish
Dec 10, 2006
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#9
Big fish or little fish? what shapè? , what filtration do you do, how many water changes. This is not a good question to asnwer as there are just too many variables - temperature, salinity and a mass of other things affect this.
Inches really don't work as my purple tang is about 5 inches long, and the size of a small plate - how does that compare to 5 one inch damsels? Weight is better ,,but it's is still very difficult to say
lets do it by surface area XD jk

i noticed that common fishes like clowns do very good in small tanks in small numbers (1-2) because they can be very territorial. they are also well know for their hardiness. so thats a factor.
 

#10
All good points. For my filtration..I have a 30gallon sump/refugium, the first compartment has my Euroreef ES-4. Currently my temp ranges from 74-81degrees with a rough average of 78degrees. I'm using a $10 hydrometer until my refractometer comes in and I hit 1.021/1.022 on each check. Ammonia & Nitrites 0.

How do I know if my bio load is more than my tank can handle? I've yet to do a water change as my tank has only been running for about a month, but when i start it will be weekly 10% water changes. Currently I lose about 4 quarts per day from evaporation.
 

Lorna

Elite Fish
Mar 3, 2005
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#11
Your salinity could be a bit higher if you are planning on a reef........which should be about 35pt or 1.025.....temp is good. But as stated it depends on what type and what fish you are planning. Why not give us an idea of your stocking plan and we will give our opinions.........and honest ones they will be from experience also....looks to be a solid start and you are asking very good questions...
 

CoolWaters

Superstar Fish
Dec 10, 2006
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Milpitas
#12
i wouldn't use thos $10 hydrometers...just go on ebay and get a refractometer for like $25 if your lucky. i switched over to a refractometer and found that my hydrometer was off by .005 a big difference....
 

#14
Various Sponges
Various Polyps: Button, Colony, Yellow Colony, Green Fluorescent Mushroom, Bullseye Mushroom, Hair Mushroom
Various LPS: Candy Cane, Brain, Purple Short Tentacle Plate
Soft Corals: Toadstool Mushroom Leather, Fiji Yellow Leather, Cabbage Leather, Cauliflower Cult
I don't see myself getting many Acropora's.

Fish/Invertebrates (non aggressive):
Sand Sifting Sea Star, Fancy Serpent Sea Star, Sea Cucumber
Blood Red Fire Shrimp, Scarlet Skunk Cleaner Shrimp
Anemones (Bulb and will put in first, and hope it doesn't move later)
Pincushion Urchin, Longspine Urchin
Clown, Mandarin, Blenny to remind me of the Benny's, Pseudochromis, blue tang, goby, and that scarface guy from Nemo

I'm trying to recoup from my startup SW costs before I grab a 48" AquaMedic T5/Halides/Lunar lights.
 

Last edited:
Sep 12, 2006
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Algonquin, IL
#15
and that scarface guy from Nemo
this type of fish is a moorish idol. i would highly recommend not getting one of those. professional aquarium-keepers have a hard time getting them to accept prepared foods. their success rate is extremely low. and i hope you aren't planning to put all of these in the same tank. is that a list of things you are thinking of or everything you plan on stocking? you probably can't do more than one starfish. i don't know how you can stock sponges, as they usually just come encrusted on live rock. a blenny, pseudochromis and mandarin all eat the same thing and the mandarin would struggle the most if they had to compete for food. i'm almost positive one of those shrimp would rip the other to pieces. urchins are a bad idea in general. the anenome might eat the smaller fish. and with that many corals, i think some would start to sting others as they wouldn't have much room in a 55.
 

Joe Fish

Superstar Fish
Apr 21, 2006
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#17
Sand sifthing star fish usually starve long term in a tank of that size. I was skeptical at first but about 6 months or so later it starved to death. I would take it off your list. They are also known for eating all the good fauna in only a few short weeks. Cucumbers do the job quite nicely.

I mainly have polyps, LPS, softies, and 2 SPS. So that sounds good.

I would be hesitant to add an urchin. I have been thinking about one myself, but the clumsiness is keeping from getting one. Not to mention they will eat many types of alges including coraline. If you can figure out a way to train it to only eat the coraline on the front glass let me know.
 

#19
I wasn't planning on getting all those fish. It would be those fish that I would do more research on and probably choose from that list.
I'll see about training the urchin to eat from the glass only. I'll put my face in the water and yell 'NO' everytime I see it on my yet to grow coraline. Is a tuxedo urchin just as bad? Doesn't seem like I can choose any of those fish from that list. :(
I'm learning how hard it is to pick fish.
 

Lorna

Elite Fish
Mar 3, 2005
3,082
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NE Indiana
#20
ahhh see that is why I suggested that you bring a list to us and we would help......I agree the moorish idol is a bad choice and they should remain in the ocean. An anemone needs a long established very very stable environment with good light and even then they will go where ever they want and would probably run over a lot of your stuff finding a spot to hang out in. Leathers are notorious for aleopathy and chemical warfare with other corals so filtration with carbon and good water changes are a must. Sand sifting stars will decimate your sand bed and starve to death.....and should only go into a large footprint with sufficient fauna to support their voracious appetite. I have a small green urchin in my 30 and he is constantly bowling things over so you may rethink an urchin. Shrimp........now a good choice I think as I am partial is a pistol shrimp/gobie pair.......the tank is too small for a tang (imho) but there are some really nice wrasses and blennies and pygmy/dwarf angels out there......just go slow and let everything settle between additions and what ever you do set up a quarantine for new additions before introducing them.