dieing fish & tank cleaing after death

Question
Hello, I set up our 20gallon tank and put 12 fish in. (from walmart) There is one shell decoration, a boat, and a few rock type decorations and rock covering the bottom in the tank. A small bubbler is in the center. So far 5 out of 12 fish have died. They've only been in there for 3 days. I've had fish many times before but I'm not an expert by any means on the subject. I don't know if there's anything I could treat with to save the other fish or clean the tank somehow. There's no specific signs of an identifiable disease or fungus. What do I do???

Answer
Hello Kim,

Fish require filtration.  I see mention of decorations and a bubbler, but not of filtration.  If you do not have a filter, please add one immediately, because they will perish without one.

Fish also require a heater.  Heating the tank to 78 degrees F is very easy.  You put the heater in, set it and plug it in.  :)  But it is absolutely a necessity.

In a 20 gallon tank, you can have 12 fish, if they are fish who stay below 1.5" each.  That goes for most fish, but if they are goldfish, they require much, much more room.  Goldfish poop a lot.  the poop poisons the water.  It gets what is called ammonia.  Have you ever smelled someone's catbox?  That's ammonia.  Imagine the fish breathing that in the water!

To combat ammonia, we keep goldfish in their own specific sized tank.  Goldfish require at least 5 gallons each, as babies and if over 3" long, require at least 25 gallons each.  When they mature more, they require up to 50 gallons apiece.  Otherwise the water will always have a yellow color and a stink.

So, back to the equasion 1" of fish per gallon, this is a standardized equasion that does not apply to goldfish or plecostamus.  

So, this means if your fish are 2", they require 2 gallons of water each.

This means - In a 20 gallon aquarium, you can have 10 2" long fish, or you can have 20 1" fish.  If the fish are juveniles, they will outgrow their size/gallon ratio and so you will have to increase the tank size as they grow.

For that reason, I recommend researching the fish before you purchase them.  Find out how large they will get.  If it says they will reach 3", only buy that fish for 3 gallons of water...because it can then grow up in its home and won't have to be transferred later.

Fish water should have no smell.

Before setting up a tank and introducing fish, you should allow the tank to run at least 2 weeks with nothing in it but a snail or two. This starts a cycle.  When the cycle is done, the fish can go in because good bacteria can now suppor them.

When you put water in, you need to use a dechlorinator product to make sure it's not poison to them.  Chlorine and chloramine are in our tap water.  Chlorine evaporates in 24 hours.  Chloramine does not.  Therefore, they need treatment.

I would drain out 50% of the water and would replace it immediately.  If there is fish waste in the water, they are breathing ammonia.  It is very harmful to the fish, deadly.

I would add a filter immediately.  One rated to 40 gallons, rather than 20.  If you buy a filter, it might say something like, "Power filter 20/40" and that filter would be okay, but if it says "10/20" it will not.  Never go with the second number.  Always go with the first, and assume it's under-rated.  When they rate filters, they do so for aquariums that are regularly maintained by experts.  They aren't thinking like the average Joe, who doesn't know all this expert stuff, so always over filter.  It won't hurt a thing.

The filter's pads need changed out monthly.

When you feed the fish, only give them enough that they can eat in one to two minutes.  Nothing should ever go to the bottom of the tank.  If they are fed properly, they are fed once a day only.  They will always beg.  But, they will live the longest lives in cleaner water.  To do so, they need to eat properly and not have waste in the tank.

The filter will be your biggest help and the heater will also.

I am SO sorry for your losses.  It's heart-wrenching when they die.

If you have further questions, please email me back, Kim, and I will do my best to assist you through this.

Please don't forget to rate my answers. :)  I volunteer because I love animals and fish and I hope to help you in this situation.

Happy fish-keeping!

Renee