How many fish can go into a 75 gallon

[nickf06gli]

The tank is 75 gallon, 48"L by 18" wide with about 75 pounds of rock on the back glass, and live sand, right now there are 2 small clowns, 3 chromis, also very very small, a 6" sand sifting star, a chocholate chip star, some kind of red star fish, a yellow tang about 3" long, and a yellow watchman gobie, and a scooter blenny, and 3 cleaner shrimp.

All my nitrates, ammonia, ph and nitrites have remained constant for the last too weeks at zero ppm, and the ph is 8.3.

So do you think it would be ok to put a few more small fish into the tank

 

[evallarta1]

From what Ive seen (and Im no expert) for a FOWLR the "general" rule is 3 gal to 1 inch of fish. And for reef its 6 gal to 1 inch of fish.

 

[lcstorc]

The general rule is one inch of full grown fish per 5 gallons of water. Even if we don't consider displacement by the rock and sand you are looking at 15 inches adult fish for that tank. The tang will easily take more than half of that. Looks like you are pretty well maxed out. The tang is really too big for that tank. They get very large and that is just not enough swimming room. Take the tang back and you will have room for several small fish.

 

[jthomps123]

The whole inches-per-gallon rule doesnt really hold - because some fish (as stated above) like tangs throw those averages out the window. The tangs inches has more to do with swimming room.
It also has alot to do with how well you take care of your tank, and how good your waste export is.
In my 75 (90 total) I have:
1 Regal Tang (juvi - this guys getting me a tank upgrade soon 3"
1 Copperbanded Butterfly 3"
1 Occ Clown - 3"
1 LawnMower Blennie - 3"
1 Green Mandarin - 3"
3 Green Chromis - 4-5" total
1 Yellow Watchman Goby - 2"
1 Green Clown Goby - 1"
1 Neon Goby - 1.5"
1 Royal Gramma - 2"

Holy crap i didnt realize I had 12 fish! + 2 Shrimp! If you include the shrimp I probably have nearing 28" of fish or so. But the majority of them are small fish - and I have zero aggression in this tank (aside from the clown chasing a chromis every now and then).

My nitrates have been zero for so long I rarely test for them anymore.
My export system is 80lbs of mature live rock, EuroReef RC135 recirc skimmer ( this thing seems so efficient that it seems i can overfeed all I want with no ill affects concerning nitrate spikes), 2" sand bed, small fuge with a tiny bit of halimeda, new phos reactor (I feed alot and need to export phosphate and silicates from my food). Oh - and plenty of flow with no dead spots in my tank - the majority of my rock is supspended off of the sandbed by stacking and PVC frame.

I have a dozen or so SPS, and a dozen or so LPS/Softies that are doing fine.

Your inverts make your livestock list seem larger than it really is, I would say if you can keep your params in check then go for a couple more small fish. I personally would rather keep many small fish than a limited # of small fish.

 

[AndtheBonus]

Ya a tang is going to kill most of your space. Like Lynn said if you trade it in to your LFS then you should have room for a few more SMALL fish.

 

[Witfull]

also you have to factor in filtration....poor filtration maybe 5-6 fish healthy....awesome filtration 8-9 fish depending on size and species.

 

[lcstorc]

The whole inches-per-gallon rule doesnt really hold - because some fish (as stated above) like tangs throw those averages out the window. The tangs inches has more to do with swimming room.
It also has alot to do with how well you take care of your tank, and how good your waste export is.

The inches per gallon is just an average like you say. A tang is obviously going to take more food and make more mess than several small gobies. It is like I said an average. You assume that each tank has some smaller and bigger fish so it averages out. Yes it also depends on filtration and maintenance. It is just a guideline.
You are going to have serious issues as the fish in your tank grow. I too bought fish planning on a upgrade before they were grown but these things have a way of not happening. Wait for the tank and then get the fish. Otherwise you will be fighting an uphill battle or giving back fish.
You don't count the current size of the fish but the adult size.

 

[nickf06gli]

I am waiting for a 120-180gallons or maybe even bigger tank to pop on the local craigslist so this tank is a 4-5 month project and then its time to upgrade, Thanks for all of the advice, the param's have been staying in check, but I do need more flow.

 

[BigJay]

the diet has a lot to do with how many fish as well. Some fish are naturally heavier polluters. Some fishes/inverts help make up for there pollution by providing clean up efforts of other pollutants. Sensitivity of certain corals make a differnce as well. How much effort you put into your tank, like carrying out a water changes religiously and keeping a very light hand in feeding can expand the quantity. Usually as the tanks age people carry out the required maintance less and less religously and the inhabitants get bigger and bigger leading down a path to disaster.
So as stated the fish per gallon is general guideline. For instance I only put 1 clown in my 14 gallon tank. But if he came out I may put 2 fire fish in his place and maybe even a small goby.
Like everything else in saltwater its very difficult to have hard and fast rules for all situtations.

 

[nickf06gli]

sounds like very sage advise. Thanks again

 

[brandon]

I agree with big jay most get lazy as the tank ages, and that leads to big downfalls later. I do water changes every week about 20%. Ive seen big improvement's in my fish and corals because of it.

 

[powrsurg]

Hello everyone,
This is a question that I have been juggling with as well. I have a 75 gallon tank with about 100 pounds of live rock. 15 inches of fish just doesnt seem right. I have read in many many places about the 1inch to every 5 gallon rule. I am not dismissing it yet as I have learned first hand that most professional advise in this hobby is true. I had a very bad first 2 months and have finally been stable for 2 months now without any tank carnage to report. Below is a list of fish in my aquarium.

Fish
Orange Butterflyfish
Koran Angel fish
Powder Brown Tang
Lunare Wrass
Falcula Butterflyfish
Spotted Cardinal Fish
Green Chromis
Four Striped Damsel
Yellow Tail Blue Damsel

Inverts
Fluorescent Green Feather Duster
Caribbean Feather Duster
Electric Blue Hermit Crab
Emerald Crab
Spotted Moon Crab
Long-Spined Sea Urchin
Pin cushion sea urchin (Pain in the A$$)
2 Scarlet Skunk Cleaner Shrimp
6 Snails
4 Bumble Bee Snails
Cowry

My chemistry is perfect. I test it every other day. Many will say I have way too many fish for a tank my size however here is what I am doing to keep my water sparkling.

1) Fluval FX5 filter with lots of carbon. I change the carbon monthly
2) 100 Pounds of live rock
3) 80 pounds of live sand.
4) I have a Protein Skimmer which is constantly running.
5) I have 2 air stones placed under the substrate for extra oxygen exchange.
6) I have a power head pointing to the surface facing the towards filter outflow.
7) two hand fulls of Chaeto used for decorative / nitrate management purposes
8) 6-8 gallon water change every other week.

Again, I am not discounting the advice yet, but it does seem that my tank is doing very well with the fish I have in it. Most of the fish have become "friendly" and swim as a school. Its pretty neat.

 

[PIMPALA]

Hello everyone,
This is a question that I have been juggling with as well. I have a 75 gallon tank with about 100 pounds of live rock. 15 inches of fish just doesnt seem right. I have read in many many places about the 1inch to every 5 gallon rule. I am not dismissing it yet as I have learned first hand that most professional advise in this hobby is true. I had a very bad first 2 months and have finally been stable for 2 months now without any tank carnage to report. Below is a list of fish in my aquarium.

Fish
Orange Butterflyfish
Koran Angel fish
Powder Brown Tang
Lunare Wrass
Falcula Butterflyfish
Spotted Cardinal Fish
Green Chromis
Four Striped Damsel
Yellow Tail Blue Damsel

Inverts
Fluorescent Green Feather Duster
Caribbean Feather Duster
Electric Blue Hermit Crab
Emerald Crab
Spotted Moon Crab
Long-Spined Sea Urchin
Pin cushion sea urchin (Pain in the A$$)
2 Scarlet Skunk Cleaner Shrimp
6 Snails
4 Bumble Bee Snails
Cowry

My chemistry is perfect. I test it every other day. Many will say I have way too many fish for a tank my size however here is what I am doing to keep my water sparkling.

1) Fluval FX5 filter with lots of carbon. I change the carbon monthly
2) 100 Pounds of live rock
3) 80 pounds of live sand.
4) I have a Protein Skimmer which is constantly running.
5) I have 2 air stones placed under the substrate for extra oxygen exchange.
6) I have a power head pointing to the surface facing the towards filter outflow.
7) two hand fulls of Chaeto used for decorative / nitrate management purposes
8) 6-8 gallon water change every other week.

Again, I am not discounting the advice yet, but it does seem that my tank is doing very well with the fish I have in it. Most of the fish have become "friendly" and swim as a school. Its pretty neat.

Is this post for real?


all those fish and a canister filter with carbon changed monthly? air stones under the substrate?

 

[powrsurg]

Yes this is for real. I never claimed to be an expert. Just digging for reasons my tank water is so clean.

 

[sk8rdn]

Best of luck to you with that.... For your inhabitant's sake.

....Broadcast in High Fidelity Stereo Sound where available....

 

[sasquatch]

2 months of stable conditions only means one thing... you are walking the edge of a fresh razor blade, if you slip... doom, the fish may get along, stress may be low but you cannot expect small water changes to to export the toxins that are building up every minute.
ps, what you perceive to be "clean water" isn't, example.. I hand you a glass of sulfuric acid... looks clean, even good enough to drink if you didn't know, but would you? no.
Believe what you like its your tank, if you decide you want to provide decent care for your fish? just ask and we can help.

 

[jpsika08]

OMG really? That amount of fish in such close quarters? Where or who has been giving you advice?

 

[StirCrayzy]

Thats just not safe. Its not impossible. But there is some debate that the fish " look happy" when really they actually release a stress induced chemical that stunts growth and leads to a shofter lifespan.
By that theory your fish will neverr outgrow the caaptive environment. And test kits will not find the proof.

Cheers though for maintaining excellent quality water for them in the meantime.
Best of luck to you.

 

[powrsurg]

In fairness to honesty and for the education of all who will seek the answer to the original post, here is what recently occurred.

The fish I had in that tank were slowly added over a period of time. I've always checked my water daily for Am, PH, Nitrates and nitrates. All were always 0. I decided to donate the eel back to the store and they gave me a discount on two fish which had a combined length of 4 inches less than the eel. Those fish were the orange butterfly and the Koran.

Within three days things started to go south. The tang and orange butterfly started to develop what looked like ich. Also ammonia spiked. It went to 2 ppm's and stayed there. I performed water changes every three days and ammonia would go back to 1ppm.

In the end the tang and orange butterfly died as well as the spotted moon crab.

Ammonia is back to 0 as well as the other nitrite and nitrate. They never budged over 0 just the ammonia.

Now I have a Chromis, pj cardinal, Koran, falcula butterfly, lunare wrass, and two damsels.

This is what I've learned.
1) size of fish is not the ultimate determinate of bio load. Some fish have more of a bioload than others.
2) somewhere between now and 7 additional inches of fish exceeds critical mass.
3) 1 inch of fish per five gallons is more realistic than 1:3.

I am the type of person who has to learn for themselves. I have learned.

PS - I wasn't looking for a Koran when I picked him up. I was captivated by its beauty and was told it was a dwarf. WRONG!! I am going to have to give this one back as well.

So 4) no matter what, never buy a fish without first researching. Don't let it's coolness and beauty get you. It will screw you every time.

I am amazed at my tank and happy I got it. I would be lying however if I didn't point out that I am disappointed by how empty it looks considering the footprint such a large tank takes up. Going with a larger tank is not the answer as it will look just as empty once it crèches critical mass.

 

[dmatt88]

In fairness to honesty and for the education of all who will seek the answer to the original post, here is what recently occurred.

The fish I had in that tank were slowly added over a period of time. I've always checked my water daily for Am, PH, Nitrates and nitrates. All were always 0. I decided to donate the eel back to the store and they gave me a discount on two fish which had a combined length of 4 inches less than the eel. Those fish were the orange butterfly and the Koran.

Within three days things started to go south. The tang and orange butterfly started to develop what looked like ich. Also ammonia spiked. It went to 2 ppm's and stayed there. I performed water changes every three days and ammonia would go back to 1ppm.

In the end the tang and orange butterfly died as well as the spotted moon crab.

Ammonia is back to 0 as well as the other nitrite and nitrate. They never budged over 0 just the ammonia.

Now I have a Chromis, pj cardinal, Koran, falcula butterfly, lunare wrass, and two damsels.

This is what I've learned.
1) size of fish is not the ultimate determinate of bio load. Some fish have more of a bioload than others.
2) somewhere between now and 7 additional inches of fish exceeds critical mass.
3) 1 inch of fish per five gallons is more realistic than 1:3.

I am the type of person who has to learn for themselves. I have learned.

PS - I wasn't looking for a Koran when I picked him up. I was captivated by its beauty and was told it was a dwarf. WRONG!! I am going to have to give this one back as well.

So 4) no matter what, never buy a fish without first researching. Don't let it's coolness and beauty get you. It will screw you every time.

I am amazed at my tank and happy I got it. I would be lying however if I didn't point out that I am disappointed by how empty it looks considering the footprint such a large tank takes up. Going with a larger tank is not the answer as it will look just as empty once it crèches critical mass.

Glad u learned n shared. I'm pushing almost 600 gallons n u had more fish than I. Plus I have a 100+ gallon sump! PS. Get a sump it'll simplify ur life.

.......thanks for listening.