Fish Behaivor

Question
Hello, i appreciate your time.

I have a new 10 gallon tank, which just finished the nitrogen cycle.  I introduced 3 Corey cats, a redtail shark, 10 tetras, and a butterfly pleco. These fish were introduced way too fast.  The tank was not even fully cycled. (i know its terrible on my part.)

I bought a master test kit.  my first test showed nitrite at 8-10.  I am assuming my fish went through an ammonia spike as well.

Current Parameters (ppm)
Ammonia 0
Nitrite 0
Nitrate 0 no more than 1
PH 7.8-8

My tank is fully cycled now and i am noticing very aggressive behavior in the tank now.  The tetras are fin nipping the other tetras, and the shark is harassing the tetras.  The Cory cats are swimming up and down the sides of the tank.

Yesterday i added a java fern plant.  I had dim blue bulbs in the tank, and just yesterday switched to 50/50 coralife 10 watt bulbs.

What could be the cause for this?  could it be the ammonia and nitrite spikes? the lighting?
what can you recommend for me?

Also my nitrate levels should be rising soon, if 3 days ago was the first time my nitrites came down to 0?



Thank you so much

Matthew  

Answer
Good evening Matthew, thank you for your question.

When you say your tank is fully cycled now, then say that you are expecting a nitrate spike, you can see yourself that your tank has not yet fully cycled. As you know, these fish were introduced too rapidly into your tank, but what you may not know is that a few of them don't belong in there at all!

The red-tailed shark grows to be about 7 inches long on average, surely you can see now that this is an inappropriate choice for a 10 gallon tank. At least a 29 gallon tank will be necessary to give this specimen ample swimming room, a 55 gallon is best to keep aggression down, as they can get territorial with their tankmates.

Crowded fish feel "edgy" just like you and me - who wants to be elbow to elbow with someone in a subway? That's how these fish feel. Besides going through the stress of being in an uncycled tank, they feel the psychological and physiological effects of crowding, which means that instead of a few thriving fish you have lots of fish that are not thriving.

Tetras encompass a large family, so you'll have to be a bit more specific. For all but the teeniest of tetras (neons or glowlights, for example, and neons are the smaller of the two) 10 tetras is just too many. So unless you are talking about 10 neon tetras, Matthew, you may have to return some of the tetras! Tetras really like to school with their own specific kind and will not usually school with other tetras in general, so if you have a couple of these and a couple of those, this will not work at all in the long run.

I am not quite sure what to tell you about your pleco. In a way, you did a better thing than purchasing a Hypostomus (common) plecostomus, which grows tens of inches long, but even at 6 inches, the butterfly pleco will still grow too big for a 10 gallon tank eventually. I can't find very much on their care, but fancy plecos are quite fussy about their water quality and will starve if they are not given their own foods. Many will accept algae wafers and all of them appreciate fresh vegetables - zucchini, cucumber, and leafy greens - weighed down and placed in the tank for them to graze at nighttime. I know that many gold nugget plecos go on hunger strikes - it is sometimes tough to acclimate wild plecos. I am not 100% certain we are talking about the same pleco, though - does your pleco look like this?

http://www.planetcatfish.com/catelog/species.php?species_id=706

Matthew, I really wish I had an easier answer for you, but the truth is that your system is overstocked in such a way that cannot be remedied with overfiltration or really keen maintenance. Return the red-tailed shark unless you plan on upgrading your tank very soon, consider returning the pleco, and analyze the tetras that you have...what is their mature size? Your tetras and cories sound fine together if the tetras are neons, if not, you should thin this number down a bit, or upgrade to at least a 15 gallon tank.

Ten gallon tanks are difficult to keep stable because of the limited surface area over this relatively small volume of water. Water changes are imperative, and with your overstocked system, two 25% water changes twice a week is not too many, trust me! Always remember to use dechlorinator if you are using tap water. The "refreshment" of water changes will help some with aggression, but the long term solution is to fix the stocking dilemma in your tank.

Take a look at these web pages for some more advice:
http://freshaquarium.about.com/
http://www.wetwebmedia.com/FWSubWebIndex/fwsubwebindex.htm

Following these pages' links, you will find lots of information and advice on stocking, freshwater aquarium maintenance, the cycling process, and much more! Take a few hours a week to read about fishkeeping, and you will be much more successful. The quality of help can be so variable at your local fish store (LFS)... this is why independent research is really the only way to excel at this hobby.

Good luck!
Nicole