Sick zebra danio.

Question
QUESTION: Hi.

I've just set up  40l coldwater tank and it's now been running for almost 2 weeks.  After 48 hours, of setting the tank up and putting the declorinator in i went to the pet store and bought some Danios and the coldwater version of the Neon Tetra (the grey/brown and red ones.. cannot remember the name.

There are 7 fish in total and this morning when i woke, my Zebra Danio was on the bottom, breathing very heavy.  He did come to the surface but got in line of the filter which made him spiral downwards several times.  He seems to have no control and i've taken him out of the main tank to another.  He's just sitting on the bottom rappidly breating!

All the other guys are fine as can be.

Are there any tips?  I somehow don't think he has swim bladder but he does seem to be a bit unstable.

Many thanks.


Jess

ANSWER: Hi Jess,

I believe you mean a White Cloud Mountain Minnow, which was nicknamed "poor man's neon tetra" back when neons were rare and expensive. Now they are one of the cheapest fish around!

I definitely know what your problem is. Your tank is not cycled! As Neale Monks, brackish expert likes to say, letting a tank sit without adding an ammonia source achieves precisely nothing - or something like that. Fishless cycling is not difficult but it does take some patience. You need:
* test kits for ammonia, nitrite, and nitrate
* ammonia source

Set up all your equipment and fill the tank with water. Then either add plain ammonia, enough so that it registers 5 ppm on a test kit. When you start seeing nitrite, you can cut that amount in half, until ammonia and nitrite are 0 ppm and nitrate begins to register. A 75-80% water change will be necessary before you add fish. Most people like to use drops of ammonia, I have never done so myself...

I find it much more convenient just to drop a piece of cocktail shrimp in the tank (for a tank your size, half a shrimp will do) and watch it degrade. This continuously adds ammonia as the shrimp decays. If that's too gross for you, feeding the empty tank a pinch of flake daily will do.

However, I am just telling you that for future reference - you are (albeit by mistake) doing it the old fashioned way right now, you are cycling the tank with fish in it. This can be very hard on the fish, but thankfully zebra danios and WCMM are both hardy enough that they should be all right. You need to act fast though, or you'll start seeing problems. Symptoms of ammonia poisoning are reddened gills, gasping for air, disorientation, and later on, things like popeye and finrot are all brought on by poor water quality.

To prevent this, do a 50% water change daily. This may sound like a lot of water to change every day, but it's really the only way to ensure the fish are safe while the tank cycles. Make sure to use dechlorinator, something like Stress Coat would be helpful, if you have it, and also try to increase aeration. WCMM especially love well oxygenated water, so an airstone or powerhead is much appreciated by this species!

In the meantime, read here about cycling and startup:
http://www.firsttankguide.net
http://freshaquarium.about.com

Both those websites are clear and concise, especially check out the section on Aquarium Startup, on the left, at the about.com site. Other fine websites to try are:

http://badmanstropicalfish.com
http://www.wetwebmedia.com

Hopefully doing some water changes will help your danio to feel better. Apart from that, aeration and Stress Coat are all you need for remedies at this point. Medication might be necessary, but don't jump the gun. Medication doesn't work if the water quality isn't right. You need 0 ppm of ammonia or nitrite - otherwise medication isn't worth trying, as it just stresses the fish out further. When nitrates register, and ammonia and nitrite (with an I) are both 0 ppm, rejoice! Your tank is cycled. If you can keep the water quality stable, your fish should not get sick if they were healthy from the start. Swim bladder issues and dropsy are diet and water quality related - zebra danios are not really prone to swim bladder issues the way, say, fancy goldfish are, so don't medicate until you know for sure what you are treating for. Ich, for example, is unmistakable, and does require treatment - although heat and salt can be used instead of medication, usually to better effect, if done right.

I hope that helps! Take care.
Nicole

---------- FOLLOW-UP ----------

QUESTION: Hi Nicole.

Thank you very much for your quick detailed reply.

Unfortunately that day, the Zebra Danios died.  However, as soon as i received your email, i did a 50% water change and have been doing for the past 2 days.  All the other fish seem to be quite healthy and active so fingers crossed i may have acted quick enough.

I am keeping the tank well oxiginated with an air stone.

May i ask your advice on how many more times you think i should change the water?  Like i said, i have made 3 water changes of 50% each time and added the correct amount of stress coat.

Once again, thank you very much for your help.


Jess

Answer
Hi again Jess,

You're welcome, I am happy to help! Sorry about your zebra danio.

It has been a while now, so your tank should be close to cycled already. Unfortunately it's impossible to tell by the naked eye, you need a test kit to let you know. The strips are less accurate than the liquid test kits, but I find them cheaper and more convenient...and close enough. So that's what I use. Since I have lots of fish tanks I use the 5-in-1 Pond test kits by Jungle labs (they also make them for aquariums) and this tests for nitrite, nitrate, pH, alkalinity and hardness. All good things to know! If you choose a liquid test kit, for about $20 (and less online) you can get a Freshwater Master Test Kit from Aquarium Pharmaceuticals, and this will be all you need for a long time.

When ammonia and nitrite are absolutely 0 ppm, and nitrates register, your tank will be all the way cycled. It takes about two weeks, give or take, for a tank to be cycled, depending on a few factors. It takes about 3 months to mature a fish tank where you can start adding delicate fish, but as far as feature fish, I recommend you stay with the two species you have, since your tank is smallish.

Feed lightly (these small fish are eager eaters but don't need much) and don't worry about gravel vacuuming until your tank has been set up for a couple of months. If there's a lot of noticeable debris on the bottom, you are overfeeding and need to cut back. It's preferable for all the food to be gone in a tank with surface feeders like yours.

If all goes well, you should be fine with just doing 25% weekly water changes as part of your regular maintenance and vacuuming the gravel maybe once a month. When your tank is mature, you might consider adding some otocinclus, the "dwarf suckermouth catfish". This fish is tiny, but likes to be in the company of its own so I try to keep it in trios. I find that no matter how diligent I am, my tanks always get algae, but these guys are perfect for small tanks and really do a superb job of keeping the algae at bay.

Just a few suggestions. Take care!
Nicole