Zebra Danios Nipping Fins? What You Must Know


Sometimes fish are like children in that they are unruly and won’t follow your wishes. It’s especially frustrating when they start to hurt each other.

And yet fin nipping isn’t an issue in some other aquariums. We’re confident that you can also accomplish this.

Are Zebra Danios Fin Nippers?

The Zebra Danios is has a reputation for being energetic and nippy. Never mind the energy, but hurting other fish shouldn’t be a norm in your aquarium.

Zebra Danios aren’t normally fin nippers. As long as conditions in your tank are favorable to them, you won’t have a problem with them nipping each other or tankmates.

So, when you indeed confirm that they attack others in your tank, you know there’s something amiss.

Why Do Danios Nip Fins?

The main reason why Zebra Danios turn nippy is stress. Stress can be caused by several reasons like:

  • A lack of numbers in its school
  • Poor water chemistry
  • Either empty or overcrowded tank
  • A new fish
  • Males wanting to breed

The good news is that these can be corrected or fixed.

How Do You Stop Fin Nipping Or Biting?

Tip #1: Take tank mate compatibility seriously

While some people take chances and go against the tide, most of these are either new hobbyists who haven’t done their research or very experienced fishkeepers who perfectly know what they’re doing. Only the latter come out successful… sometimes.

Zebra Danio Nipping FIn
Zebra Danio Nipping FIns

As a general rule, don’t mix slow-moving fish with fast-moving ones. Exceptions exist, and we’ve even discussed the combination of Zebra Danios and Angelfish before in our article here. But that entails a lot of planning, space, and a ready backup for the possibility that things don’t work out.

Zebra Danios are fast-moving fish and they are compatible with other darting and peaceful fish like Guppies, Swordtails, Platies, Tetras, and Gouramis. You may notice that the sizes of these don’t veer too far from the Danios’.

On the other hand, avoid large fish that can fit the Danios in their mouths. Whether aggressive or not, you won’t be able to stop the natural behavior of big fish eating smaller fish.

Note: There is a certain, lesser-known Danio variety that’s very aggressive and nippy. It’s called the Green-barred Danio (Barillus pulchellus). These are larger at around 4 ½ inches in length at maturity. They prefer crystal clear water with a strong current. They are not good community fish at all and would require a species-only tank with a big school of them.

Tip #2: Respect the schooling principle

This is a fault many of us are guilty of. We try to keep a couple of schooling fish hoping everything will be alright.

However, for Zebra Danios and other similar schooling species, a group of 6 or more fish is required to keep aggression and territorialism at bay. Remember that these species feel safer in bigger numbers especially when around bigger or more numerous fish. Without their schoolmates, they feel threatened and nervous and will resort to nipping to defend themselves.

For a calmer community tank, go beyond that number. It will be better if you have a group of around 8 to 14 Danios. You can even add in GloFish Danios and they’ll include themselves in the school for protection. And you’ll benefit from watching the interesting behavior they exhibit as a whole unit.

Zebra Danios nipping fins
Zebra Danios nipping fins?

Take note that a fight for hierarchy might take place once new Danios arrive. In every group, there is a dominant fish who will always want to show that he’s the boss, especially to newcomers. Chasing might become prevalent, but fin nipping shouldn’t result in death. The excitement should tone down after several days.

Remember, though, that more fish require more space. A school of Zebra Danios alonewould require you to have no smaller than a 20-gallon. Now factor in their tankmates and add to find the appropriate tank size.

Tip #3: Overcrowding

Still related to tank size, overcrowding becomes a problem with a tank that’s too small for its inhabitants. Fights will ensue with the lack of resources—mainly the scarcity of space or food.

The obvious solution is to get a bigger tank or to rehome some of your fish.

Tip #4: Check your water and tank setup

One of the things you need to do as a fishkeeper is to imitate the setup of the fish’s natural habitat. Not only does this include space as we mentioned above, but the temperature and the quality of the water as well.

Zebra Danios react to bad water. They may be hardy and easily adaptable but it’s no reason to use tap water or let your water get contaminated especially by toxins like ammonia and nitrite. If you need more information on cycling your tank, read about faster tank cycling here or some of the basics of tank water cycling here.

Stressed Danios will not only turn desperate and start to hurt tankmates, they might even jump out of your aquarium! So before this happens, make sure your parameters fall into the ranges that we’ve listed here.

Do Zebra Danios Nip Fins
Do Zebra Danios Nip Fins?

While water test strips are useful, sometimes it’s more beneficial to use a master test kit (the ones with the test tubes). They’re great if you need a more accurate reading of your water chemistry.

Using a master test kit is easy. They come with complete instructions and apparatuses. We also recommend you pick up some 10ml syringes or medicine droppers so you don’t have to dip your test tubes into the tank to retrieve water samples. They make measuring and testing more convenient.

Tip #5: Go natural with live plants

A good tank setup also includes live plants. You might like those perfect plastic plants from the pet store but live plants bring a lot of benefits into your aquarium like oxygen, nutrients, shelter, and a distraction to aggression. We discuss the benefits of live plants on our page here.

If you’re worried that plants will become burdensome to take care of, don’t worry there are some low maintenance plants that you can add in like Java fern, Amazon swords, Java moss, or Hornwort. All they need is medium light and a little trimming now and then. Just make sure to leave some open spaces for your fish to swim in.

There are times when your Danios might nip on the plants themselves. But don’t worry, they are omnivores so taking a few bites off of your leaves won’t hurt them. Besides, you’d rather they nip on the plants than their tankmates, right?

Supplement live plants with rocks, driftwood, and other structures that can serve as hiding places for the fish.

Tip #6: Let them mate

Male Zebra Danios are eager maters. When it’s time to breed, they’ll chase after females relentlessly and will sometimes nip. That’s why we advise keeping 2 to 3 females for every male just like livebearers. When there are enough females to entertain the males, the nipping stops.

In case you don’t want them producing fry (as they can produce a lot), let them eat the eggs once the females produce them.

Final Thoughts

Zebra Danios aren’t very demanding fish and so nipping is a sign that their stress levels are high. A little adjustment here and there will help them avoid this behavior and make your tank a more pleasant one for all your fish and of course, for you.

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