Too many fish to add at once?

[roxcarr]

Hi - I have a 55 gallon tank w/4 largish angels, 3 2" roseline sharks, 3 julii corys, 1 dwarf gourami, and a 6" ghost knife. I was out cruising the fish stores yesterday, and decided I would like to add 3 zebra loaches, and 3 red swordtails. They are all about 2" long. Is this too many fish to add at once? I've been looking for the zebra loaches for a while. The swordtails are a whim. I'm also thinking about adding one or two mollies - the kind with the long fins. I did some reading about them last night, and I'm kind of confused. Do they need brackish water? Thanks in advance for any responses.

[Mzungu]

First off, do you have a quarantine tank? I wouldn't add anyone to an established tank without first quarantining them.

Second, no, mollies don't need brackish water. Clean water is perfectly adequate! But some swear by salt in livebearer tanks, and some don't. It's really up to you, but I don't believe that those who swear by the addition of salt are talking amounts that would produce truly brackish water. I think they're just adding something along the lines of a few teaspoons per 10g or so.

[roxcarr]

I already add aquarium salt when I do water changes, so that's no problem. Have you lost fish by adding new fish without quarantining in the past? I looked at these fish yesterday, and they looked really healthy.
A quarantine tank is in my future - just not in the budget right now.

[Jason]

I've had an incident where I bought an angelfish and put it in my tank. The next day, my tank had ICH!

Since then, I've had a quarantine tank.

[eklikewhoa]

You can get by without a QT tank, I've done so for a long time but I'm very caustious about where I get fish from and the condition they are in.

[eklikewhoa]

Mzungu pretty much covered the basis.

As long as your tank is healthy and established adding the mount of fish will be ok. I take the extra precaution of feeding less before and a few days after when adding new fish.

[roxcarr]

Glad you told me that. I would feed them more immediately after because I would want the older fish to be full so they wouldn't pick on the new ones. But what you're saying is because of ammonia levels, right?

[eklikewhoa]

Yes, to not overload the biological filtration.

[Mzungu]

I still wouldn't do it without QTing. No matter how healthy the fish look, nor how reliable the source, there's just no telling. I wouldn't even tell someone to add even my fish to their established tank without quarantine, even if my fish have been healthy for years. The stress and such of the move could bring out anything, in your fish or in the new fish. You just never know. I'd rather be sure than to have the fish get sick or die. :(

[Complexity]

I must agree with Mzungu's advice regarding a quarantine tank (Q/T). If saving money is the concern, then by all means, quarantine the fish before adding them to an established tank.

Every time you add a new fish to your tank, you take a risk of adding a variety of parasites and diseases, as well. These parasites and diseases can infect all your existing fish which can lead to very costly treatments, many of which are not successful. Some treatments, such as certain ich treatments, can permanently stain the silicon and decor in your tank, ruining them. So it's a gamble. If you can afford to replace all your fish, decor, and even the tank itself, then don't use a Q/T. But if you want to be certain you don't have to buy all that all over again, then don't put it at risk by adding new fish without quarantining them first.

On the other hand, if you put new fish in a Q/T and they prove to have parasites or disease, they can be much more easily treated in the Q/T. The Q/T is usually smaller which means it will take less medication to treat the fish. You can keep the tank without substrate which helps maintaining a much cleaner environment during the treatment process. There is no concern as to whether the medications will harm the good bacteria because most Q/Ts receive frequent water changes to handle ammonia, nitrite, and nitrate levels.

Q/Ts are not expensive. I've used simple 5g and 10g tanks for Q/Ts before. All you need is the tank, a filter, and some basic decorations to help the fish feel safe. Once you get one (or two or more) Q/Ts, you can use them over and over again, storing them in between uses. Even cheap used tanks work just fine. I currently have two 10g tanks for Q/Ts (or hospital tanks, if ever needed).

Having said all that, I must admit that I do not always quarantine all my fish before adding them to my tanks. My decision on when to quarantine a fish or not depends on many factors, including the source. I also run uv sterilizers on my tank 24/7 which helps (but they aren't a guarantee). However, I know each time I do add fish directly into my tanks, I'm taking a risk of losing all my fish.

There have been times in which I have been so very glad I did quarantine fish as the fish did end up with ich or other problems which I was able to treat successful in the Q/T. There have been times in which I have read threads from people who did not quarantine their fish and have watched all their fish get infected and die, one by one, while they were desperately trying to medicate them. It's heartbreaking (and very expensive). So there is no question in my mind that a Q/T is well worth the bother and expense. It's just a matter of how much you're willing to gamble.

[Complexity]

Oh, and regarding your actual original question... I don't think adding that many fish at once is a problem as long as you keep a close eye on them, feed sparingly, and make sure you keep up with your water changes. The bacteria in the tank will usually multiply rapidly to make up for the extra bioload. You may need to do extra water changes for a week or two if you get an ammonia or nitrite spike.

Signs to look for are gasping, clamped fins, flashing (fish rubbing against the substrate or decor), and fish swimming closer to the surface of the tank than normal. If you see any of these signs, perform a 50% water change and see if that resolves the problem. If not, then check for diseases, such as spots or fuzz on the fish.

[roxcarr]

I want to ask another question about the quarantine tank. Does it have to be cycled? You said you store yours in between uses. If it has to be cycled, wouldn't it need to be kept up and running at all times?

[rmalford]

There's a right way and there's a wrong way. I added 20 fish directly into my stocked 125g last night.

WRONG WAY

[eklikewhoa]

I added 50 fish to one of my tanks at once, my other tank got 34 fish added which started with 5.

Depends on the person or the person's method I guess.

[rmalford]

I added 50 fish to one of my tanks at once, my other tank got 34 fish added which started with 5.

Depends on the person or the person's method I guess.

What were the fish and size of the tanks you are speaking of?