Fish arent eating

Question
Hi.  I am a very amateur hobbyist, but I love fish.  I have a 55 liter tank (about 14.6 gallons) with 6 fish in it: 1 dalmatian molly (2 in), 4 orange platies (total 6 inches-ish), and a plecostomus (4 in).  I also have about 8 ghost shrimp who like to hide out in my plant.  My tank has been set up for about 10 weeks.  I use a PENGUIN BIO WHEEL 100 water filter.  I have only changed the water once, and I changed a little less than half.  I don't put any treatments into the water, and i haven't tested it either.  I use tap water, and I don't have a heater.  I've had one dalmatian die already, and right now my fish aren't eating (except for the pleko, who's getting fat eating the flakes that fall to the bottom) and the shrimp, who I feel are thriving.  I haven't noticed any significant color changes, behavior changes, apart from them not eating.  They take a bite of the food I give them (I have tried tetramin tropical flakes, which they ate for a while but then stopped, tetracolor flakes, and now I'm trying Brine shrimp flakes).  Do you have any suggestions on how I can get my fish to eat again?  Oh, did i mention one of my platies is pregnant? she's been preggers since I bought her about 9 weeks ago.

Answer
Hi Stephen;

I see a couple of problems that could be contributing to your fishes' appetite loss. Those types of fish (mollies and platies) usually have strong appetites. They should be hungry all the time so there is something wrong. Before I explain more, let's try to get the fish feeling better to they will eat. The first thing you should do at this point is make a water change of 25% every day for the next 3 days. Fresh clean water is very good for the appetite. But, be sure the new water is the same temperature as the tank water and use a water conditioner if you are hooked up to a municipal water company. If you have "well water" or some other source that you know is not treated with anything for public use, you could get away without using water conditioner. But a complete water conditioner does more than remove additives from the water company. It helps with stress and binds trace metals too so it's still good to use. Cut back on food until the fish start showing strong signs of being interested in eating again.

If the room temperature where your tank is ever goes below 76f, your tank needs a heater. Temperature fluctuations can cause your fish to get sick. They need consistent temperature and a thermostatically controlled heater will provide that.

Also, get the tank water tested. Your local fish store can test it for you, or you can buy your own kits and do them at home. I recommend home testing so you can do them every day when you notice a problem. You need to know what the ammonia, nitrite and nitrate levels are. Also, Let me know what the readings on the tests are so I can help you determine what's going on. If you have the fish store do the tests, get the actual readings on each one. Write them down so you can report them to me. Don't let them tell you "it's fine" or "it's a little off". We need actual numbers to work with. Otherwise, we won't know if anything we are doing is helping if those first readings report back negatively.

The main problem I see is that there has only been one water change in a 10 week old tank. There should have been several by now. Even new tanks need a weekly 25% water change. Many experts recommend 10% to 15% but I always recommend 25%. In my experience it works very well to keep ahead of the biological waste. For now, as I said, make a 25% change daily for 3 days to help the fish feel better. It will reduce any waste toxins that are building up and usually rejuvenates the fish.

Your tank also has quite a few inhabitants for such a new system. It may be having a hard time biologically balancing because it's overcrowded and waste toxins could be making the fish feel sick. Those fish are all going to grow and plecos are very messy guys. The typical general basic rule for stocking community tanks with smaller types of fish is "one inch of fish per gallon", but...the pleco doesn't apply. He gets too large and messy. Let me know what kind he is and we can figure it out from there.

Look for signs of illness in your fish too. Are there any spots, dots, swellings, redness, strange behavior such as breathing at the top or hiding? Fish will stop eating if something is irritating them such as a parasite or infection of some type. Let me know what you see on them.

I hope they do okay. Get back to me as soon as you can so we can get those guys back on track again. While you wait for my response after your followup, take a look at the following web pages to help you know more about new tanks and keeping a healthy tank and fish long term;

http://www.firsttankguide.net/

http://expert-fish-help.xanga.com/

http://fins.actwin.com/mirror/begin-intro.html#success-tips

http://freshaquarium.about.com/od/aquariumstartup/a/newtankmistakes.htm

http://www.bestfish.com/breakin.html

http://www.firsttankguide.net/myths.php

At Your Service;
Chris Robbins