tropical fish/aquarium

Question
QUESTION: hi lynda,
 i went on holiday on 8th june 09 for a week, when i returned i found 14 dead fish and noticed my heater had unplugged. i got them out, did a 1/3 water change and plugged it back in. my water is constantly like a white cloud and fish are still dying. i had water tested and the man said i 'had a LITTLE nitrite' in it so he recommended microbe-lift xtreme and to do 50% water changes every 2 days. i have done this but yet my fish still die and it looks as though they have white-spot so i turned the heat of my tank up to prevent white-spot living (or so im told) my water is normally very clean and my fish were always happy. they now act strange and most hide all the time. please can you help. oh iv had my tank for about a year. thanks

ANSWER: Hi Lee,
I'm sorry you lost your fish.  I don't think it the cause is your heater, unless your water went really low.  How low did your water go?  What kind of fish are you keeping, and how big is your aquarium?  I would need to know this please, and I will get right back to you.
Lynda

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QUESTION: hi linda,
 sorry it was kept brief as i typed a long one and when i clicked to go forward it didnt work and i lost it all so i typed really quick. right here we go, i dont fully know what my water went down to as i never thought to check, my aquarium is a b-shaped open top tank holding approx 120L. i kept angel fish, silver sharks, neon tetra, penguin tetra, another kind of tetra, guppy's, plec, silver tip ?, RED-TAILED SHARK, A KIND OF GOURAMI, 4 TIGER BARB, ORANGE BARB, 2 PINK BOTTOM FEEDERS ? AND 2 FROGS. the fish in capitals are still alive apart from 1 tiger barb that died last night. when i first did my 1/3 water change when i got back i swapped my cousins filter that she was no longer using for mine as mine had a sucker missing and was falling off the glass all the time. they are the exact same filter. hope this helps.
Lee

Answer
Hi Lee,
Your water may have gone down, but this did not kill your fish.  Even a small amount of nitrite is dangerous, as dangerous as ammonia.  Your tank is overstocked, overstocked tanks bring lots of different diseases to fish.  For example, an Angel fish needs 10 gallons of water, 2 angels 20 gallons and so on.  Imagine all the fish you had in your tank, it is no wonder that they died, and are still dying.  A red tail shark grows to 6 inches.  They are also aggressive, and can easily terrify fish once they get to 3 inches.  Tiger barbs should never be kept with Angels.  Silver sharks need big tanks.  Plecos get too big for a 30 gallon tank, and are quite messy polluting your water. Plecos count as a fish too.  Stressed fish, living with tankmates which they should not be living with, and an aquarium too small will eventually die.  Angels are cichlids, and must have a territory.  In this situation, they had no territory, thus stressing them more.  (It was bound to happen one day)  It is just coincidence that it happened while you were away.  Ammonia converts to nitrites, and when a tank is overstock, fish will die.  When ammonia levels fall to zero, elevated nitrites will soon follow.  This causes the fish blood to turn brown, they call it "Brown Blood Disease"  The blood can no longer bring oxygen to the fish, even though their is plenty of oxygen in the water.  Some fish can tolerate higher levels of nitrite, which is why they have not all died.  Others die suddenly with no sign of illness.  Damage will occur to fish that are exposed to nitrites over a period of time.  Their immune system weakens, and any disease may occur.  Their liver will be damaged, gills, and blood cells, and eventually the fish die of lack of oxygen.  You must treat the remaining fish in the hope to save them, or bring them back to the Pet Store for a credit, and let your tank cycle with no fish in it.  If this is impossible for you to do, add air stones, bring lots of oxygen to the tank.  Add 1/2 ounce of aquarium salt to one gallon of water which will help.  Reduce feedings.  Continue doing water changes everyday.   
Do not add anymore fish.  
If you can bring them back for a credit, let your water run until it is free of ammonia, nitrites zero, and low nitrates.  When adding fish, do this very very slowly.  Add two, wait one week, and check your water, if your chemistry is right, add one or two more, and so on.  Never add fish all at once to a tank, this would change your chemistry, and all your fish would die.  Make sure your fish are compatible.  Inquire what size the fish will grow to, and avoid putting fish that grow too big in your tank.  Even if you buy them small, you must calculate the size they reach at adulthood.  Big fish in small tanks cannot grow healthy.  Their growth is stunted, and their internal organs have no place to grow, which leads to death.   Many people make this mistake in fishkeeping, we all learn from our mistakes.  We have all encountered problems, but with the problems comes experience, and knowledge.  We learn something new all the time.  Do not get discouraged.  It is always best to read or ask about fish before you put them in your tank.  Often pet stores give you wrong advice.  They are there to sell, and that is their main goal.  We bring fish out of their home to please us, we must try to make their lives as comfortable as we possibly can, giving them a resemblance of what they are use to, what they like, how their homes must be set up, and lots of space to swim.
As for "mycrobe life extreme" I cannot comment on it as I have never used it.  I would recommend siphoning your water from the bottom, and the use "Stress Coat"
I hope you can save them, it's heartbreaking to see all your fish die, I can only imagine the feeling.
Write me anytime if you need more information.
Lynda