How Many Fish For a 25G ?

[Charith1986]

Hi, I am cycling my 25g tank and planing to keep fish and few SPS and anemone.

For how many fish I should limit my tank ?

I dont have a skimmer but do weekly 10% water change and if needed even a higher amount of water change in case my tank parameters for SPS are not in line.

[Clown79]

I have 4 fish in mine.

[Charith1986]

59 minutes ago, Clown79 said:

I have 4 fish in mine.

Tahnks, what are they and do you have corals in ur tank ?

[Clown79]

My tank is full of corals.

 

I have 2 clowns, a bangaii, and a midas blenny

[Tired]

Zero tangs, or 10 eviota gobies. 

 

Three factors determine what fish you can keep in a tank of any given size: how much space the fish needs to move, how much territory the fish claims, and how much bio-load the fish produces.

Freshwater rainbowfish don't get very large, but need a large tank because they move a lot. Anglerfish sit in one place most of the day, and as such don't need a very large tank, even though a lot of them can be rather large. 

Some aggressive fish can claim an entire 25gal to themself, and will relentlessly bully any other fish in the space. Some fish will happily put up with anything else. 

The larger the fish, the more bio-load it adds. The higher your bio-load, the more water changes you have to do, and you'll eventually reach a point where you can't keep up with anything reasonable. Keep in mind that it's not length that's important in bio-load, it's the whole mass of the fish. A tall-bodied 4" fish can have more bioload than a very slim 6" fish.

 

In a 25gal, you should be able to keep 3-5 small, nonaggressive fish. Things in about the 2-4" range, though 4" fish should be only slim ones. 

Fish that are aggressive but have very small territories, ones that claim a cave and stay just in that, are fine. If you're planning on anemones, clownfish are always nice- a pair of ocelliaris clowns will do the trick. I like clown gobies because they're not aggressive, their bad-tasting slime coat protects them from bullying, they're cute, and they can sit in a wide variety of stinging corals completely unharmed. Shrimpgobies (preferably paired with pistol shrimp) are great. Dartfish should be added first because they're very shy, and MUST have a lid (though you should really have a lid for all mobile animals), but are very pretty. If you exclusively choose very small fish (2" and under), you could have 6 or more. 

 

Start with 1 or 2 fish. Keep in mind that they'll grow- do NOT take them only as the size they are now, but at the size they will be as adults. See how that activity feels, make sure your parameters stay under control, and you can add from there. No more than 1 new fish a week, unless you have to add them as a pair. Preferably no more than 1 new fish a month. 

[Charith1986]

7 hours ago, Tired said:

Zero tangs, or 10 eviota gobies. 

 

Three factors determine what fish you can keep in a tank of any given size: how much space the fish needs to move, how much territory the fish claims, and how much bio-load the fish produces.

Freshwater rainbowfish don't get very large, but need a large tank because they move a lot. Anglerfish sit in one place most of the day, and as such don't need a very large tank, even though a lot of them can be rather large. 

Some aggressive fish can claim an entire 25gal to themself, and will relentlessly bully any other fish in the space. Some fish will happily put up with anything else. 

The larger the fish, the more bio-load it adds. The higher your bio-load, the more water changes you have to do, and you'll eventually reach a point where you can't keep up with anything reasonable. Keep in mind that it's not length that's important in bio-load, it's the whole mass of the fish. A tall-bodied 4" fish can have more bioload than a very slim 6" fish.

 

In a 25gal, you should be able to keep 3-5 small, nonaggressive fish. Things in about the 2-4" range, though 4" fish should be only slim ones. 

Fish that are aggressive but have very small territories, ones that claim a cave and stay just in that, are fine. If you're planning on anemones, clownfish are always nice- a pair of ocelliaris clowns will do the trick. I like clown gobies because they're not aggressive, their bad-tasting slime coat protects them from bullying, they're cute, and they can sit in a wide variety of stinging corals completely unharmed. Shrimpgobies (preferably paired with pistol shrimp) are great. Dartfish should be added first because they're very shy, and MUST have a lid (though you should really have a lid for all mobile animals), but are very pretty. If you exclusively choose very small fish (2" and under), you could have 6 or more. 

 

Start with 1 or 2 fish. Keep in mind that they'll grow- do NOT take them only as the size they are now, but at the size they will be as adults. See how that activity feels, make sure your parameters stay under control, and you can add from there. No more than 1 new fish a week, unless you have to add them as a pair. Preferably no more than 1 new fish a month. 

Thanks, can a gobie and a blenny can be there in the same tank ?

[Charith1986]

7 hours ago, Clown79 said:

My tank is full of corals.

 

I have 2 clowns, a bangaii, and a midas blenny

Thanks, before trying zoas , is it wise to try an anemone first ?

[Tired]

Gobies and blennies can sometimes coexist, but because they're similar, will sometimes fight. Your best bet is to pick species that aren't similar, like a shrimpgoby with a blenny that perches on the rocks.

 

You've got it backwards. Zoas are fairly hardy, so can be your first corals. Anemones are more fragile, and should only go in tanks that are at least a few months old, or have been set up with very good live rock. 

[Charith1986]

15 minutes ago, Tired said:

Gobies and blennies can sometimes coexist, but because they're similar, will sometimes fight. Your best bet is to pick species that aren't similar, like a shrimpgoby with a blenny that perches on the rocks.

 

You've got it backwards. Zoas are fairly hardy, so can be your first corals. Anemones are more fragile, and should only go in tanks that are at least a few months old, or have been set up with very good live rock. 

Thanks, my tank is less than one month old, so how long do i need to wait till i introduce a zoa ?

[Thrassian Atoll]

I would say 4-5.  I had 5 in my 25 lagoon.

[Charith1986]

2 minutes ago, Thrassian Atoll said:

I would say 4-5.  I had 5 in my 25 lagoon.

Hi, what are they ?

can u send some photos of ur 25g tank ?

 

[Thrassian Atoll]

5 minutes ago, Charith1986 said:

Hi, what are they ?

can u send some photos of ur 25g tank ?

 

That’s a great question!  It’s been a few years.  😂. I don’t have that tank anymore.  
 

I think I had a Helfrichi firefish, Midas blenny, Yasha goby, black cap basslet, and something else...I can’t think of the last one.  

[Tired]

If your parameters are stable, you can try some hardy corals like zoas. 

 

Also, for future reference, you don't need to quote a forum post directly above yours. Quoting is for when you're referring to a post that's several posts away, even on a previous page, where it's not obvious what you're referring to. 

[Charith1986]

Hey thanks, sorry about that. Yes after refering to various forums here I am confused which tank i should start with for Zoas.

 

I feel like I should go with 25g one just because there is a constant water flow in it compared to 10g one. I will let the tank be run for one month or so and weekly doing water changes.

 

will check the parameters before adding corals. thanks

[Tired]

You may not want to do a weekly water change, especially not to start out with. You need nutrients in the water to feed your corals, so you should do water changes when nutrients are too high or other things (calcium, magnesium, etc) are too low. It's better to test your water every few days and figure out how often you should change the water from that, than just assume that any given schedule is good. 

 

You should put corals in whichever tank is cycled and has proper equipment. 

 

Do you have any life at all? Now is probably a good time to add cleanup crew, so they can stay on top of your algae, and so they can eat some food and produce some nutrients and help the system adjust.

[Charith1986]

I have one clown each in both tanks. Plus i give one drop of Pro Bio S (AF) bacteria daily

[Tired]

Why are you still adding bacteria? Does your tank not seem to be cycled? 

 

Do you have cleanup crews? 

[Charith1986]

my LFS told me to add one drop each for two weeks and after that one drop in each water change.

I am doing a nitrate test tomorrow, so i can check whether its cycled or not.

No cleanup crew, the strange thing is tonight i switched my tank lights and searched the live rocks with a torch, there are living insects on them

 

who are they ? are they harmful ?

[Tired]

They're probably copepods and amphipods, which usually come in on live rock. It's impossible to be sure without pictures. 

 

You should do some reading on common hitchhikers that come in on live rock, so you know what you're looking at. You also need to get your cleanup crew in, or at least the start of it. 

 

Also, if your LFS told you to put fish in a tank that's not yet cycled, they give very bad advice. You cycle the tank FIRST, completely, and then add fish and other animals.

[Charith1986]

yes from what i see they looks like copepods and amphipods.

 

when i add cleanup crews will they help to get rid of these pests ? I am in no hurry to add any more fish soon.

[Clown79]

1 hour ago, Charith1986 said:

yes from what i see they looks like copepods and amphipods.

 

when i add cleanup crews will they help to get rid of these pests ? I am in no hurry to add any more fish soon.

Copepods and amphipods are not pests.

[Tired]

Copepods and amphipods are beneficial. Amphipods can overpopulate and bother corals, but that's generally not a problem when you have fish. Copepods in particular are vital to a healthy reef, and both of them provide food for your fish. 

 

Cleanup crews eat algae and detritus. They help keep the tank clean, and keep the algae relatively under control. Snails, hermit crabs, that sort of thing.

 

You're supposed to cycle a tank, then add cleanup crew, then later add fish and coral. How did you wind up adding fish during the cycle, with no cleanup crew? Wherever you got that advice, stop taking advice from there.