How Many Fish?

[FishFanaticSyd]

How many fish could I add to my 24.9 U.S. gallon marine tank? I have a 65g rated skimmer, and 30g and 40g powerheads powering an undergravel filtration system. My tank temp is around 75 degrees Fahrenheit. I have a Coral Beauty dwarf angelfish, a Royal Gramma basslet, and a true (tank raised) percula clown. What are the best choices for fish in my tank? Looking for something reef safe in case I decide to convert to reef later on. Thanks, FFS.

[bribo12]

I'd say you're stocked especially with the angel in there. Also, centropyge Angels are hit or miss with reef safeness so watch the coral beauty


Sent from my iPhone using Aquarium Advice

[FishFanaticSyd]

Are you sure? Aqadvisor.com says I am 72% stocked... would a live rock filter help? It just seems kinda lonely in there...

[bribo12]

Yes imo you are stocked. That coral beauty will get almost 4" long and is quite an active swimmer. Sw fish can be quite territorial especially dwarf Angels. I had a potters in a 40 and he looked huge in the tank plus he was the boss.

Percula clowns and the gramma will get around 3" as well. That's a decent amount of medium fish in that size tank. If anything maybe add another clown but that is pushing it imo.


Sent from my iPhone using Aquarium Advice

[melosu58]

I too say you are overstocked. Also that under gravel filtration system will become a nitrate factory and hurt your corals. I would ditch it.

[Sniperhank]

Ugh, Aquadvisor...it might be accurate for freshwater stuff from what I hear, but they sure don't understand how saltwater works.
As per the live rock, you should have 1 lbs of rock per gallon in your system. It is your main filtration for saltwater.

[FishFanaticSyd]

I am gradually building up to the 1lb. per gallon. Are you sure about the undergravel filter? I have read 2 books specifically on marine tanks and they say it is a good filter...

[Sniperhank]

They are pretty awful in saltwater setups. Not to mention how easily they can get clogged up with all the sand, algae, bacteria growth, and live critters your sand bed will develop as it matures.

[PB_Smith]

the biggest problem with undergravel filters is that because there are no moving parts, people often assume it's a "set it & forget it" thing. UG filters require as much regular maintenance as any other type. Using a gravel vac every water change and routinely siphoning from under the plates go a long way to preventing the compacting issues and muck build-up.


Now undergravel filters and canister filters are NOT nitrate factories as is often mentioned.
The fish, other livestock and the bacteria are the nitrate factories. The reason certain types have gained that reputation is because they trap lots of detritus and if poor care and maintenance practices are employed, then you have issues.
In actuality undergravel filters are one of the best methods for biological filtration, if properly maintained.


Now having said all that, you will ultimately have better success, especially with a reef tank by not using an UG filter. The reason being is that in order to maintain it properly, you need to disturb the substrate frequently. While that really would present no issues in a fish only set-up, in a reef the micro-flora and fauna that reside in the substrate can be a vital link in the chain of maintaining equilibrium in a reef environment, so the frequent disturbing of the substrate could present issues.
Also in a reef tank we tend to setup the rockwork, coral grows and the rock is pretty much set in place. That is a problem because it precludes vaccing the entire gravel bed.
So undergravel filters are great in certain applications, but in a reef tank they can present more obstacles than solutions.


My best personal success with UG filters has been smaller freshwater, planted tanks.
I did have one on my reef tank at first, but ditched it when I upgraded for the reasons I cited above.
Hope that answers your question more fully.

[PB_Smith]

Originally Posted by FishFanaticSyd

I am gradually building up to the 1lb. per gallon. Are you sure about the undergravel filter? I have read 2 books specifically on marine tanks and they say it is a good filter...

when were the books published?

[FishFanaticSyd]

Im not sure... when the books were published I mean. I siphon most of the gravel every water change. I have not had any problems so far, and I DO NOT HAVE SAND. I have coral gravel. My filter is run by 30 and 40 gallon rated powerheads. I siliconed my plates to the bottom of the tank so nothing could sneak in around them.

[FishFanaticSyd]

Books were published in 1981 and 1987 respectively. Angelfish taken care of, he is out of the tank. Is there any stocking limit on inverts? And would, say, a black and white ocellaris or percula clown be alright?