Mysterious Deaths (?)

[JohnnyKeroscene]

Hey guys,

Recently I had introduced a white/yellow balloon molly (looks pregnant), 2 blue female guppies and a sunburst platy

into a (20g)tank that already contained a angel fish, fancy tailed gold fish, and two very small koi.

We've had the tank for well over a year now, as well as the goldfish and kois (the angel is somewhat new to the tank but not as new as the above group)
they all lived just fine for about 2 weeks, before i had found one of the blue guppies dead.

I wasn't too worried about this, i just went to remove the dead guppy and keep an eye on the tank.
approximately 2-3 days later we had found our 2 kois dead as well as the last guppy shredded corpse

those koi had a special place in my heart, and cried that they had died so suddenly, after having them for so long.

Anyways I suppose my question would be
What were the chances I introduced something into the tank that happen to only effect the koi?

I'm very worried about my number one lil fishy in there though, the fancy tailed gold fish named milky.
(I never knew I could get so attached to fish before!)

 

[Steve H.]

What are the stats on your water? That's where I would start.
You doubled the amount of inhabitants of the tank...you might have really increased your bioload to more than what your filter can handle.
And, did you recently increase the temp of the water for the angelfish?
Although, I would think the koi would be resilient enough to take one or the other as far as an ammonia spike or an increase in temp, but maybe not both.

Someone here will definitely know how to help you. But start with your water, and start ruling things out.

 

[Steve H.]

Sorry about that...computer spasm, and posted the same thing 4 times

 

[Steve H.]

W

 

[Steve H.]

ng

 

[JohnnyKeroscene]

definitely something I want to do the second I'm not sick anymore X _x

We also plan on doing a 50% water change since it's about that time anyways

 

[onidrase]

Well, you kinda kept koi, a fish that grow to be well over 2 feet long, in a 20 gallon tank. That's like keeping a goldfish in a half gallon bowl imho. They should be kept in large koi ponds, 500 gallons minimum, given their adult size. they're not really suitable for indoor aquaria. They might have died simply from growth stunting.

 

[gforce17]

I may be being thick but what does imho mean?

 

[Gilli]

Its short for in my humble opinion.

Koi and goldfish are cold water fish and shouldn't be mixed with tropical as they need different temperatures and they need different dietary requirements, breeding requirements, filtration requirements etc. They also produce an awful lot of poop which can affect the water quality. Putting cold water fish in tropical temp water will also shorten their lifespan.

You may well have introduced disease problems with putting the new fish in, or created water quality issues if you overloaded the bio load. You really need to be testing your water quality with a liquid testing kit on a regular basis or you have no idea whats going on and be able to correct it before problems worsen - its the very first thing you should do if you notice any sort of problem.

 

[Steve H.]

Its short for in my humble opinion.

Koi and goldfish are cold water fish and shouldn't be mixed with tropical as they need different temperatures and they need different dietary requirements, breeding requirements, filtration requirements etc. They also produce an awful lot of poop which can affect the water quality. Putting cold water fish in tropical temp water will also shorten their lifespan.

You may well have introduced disease problems with putting the new fish in, or created water quality issues if you overloaded the bio load. You really need to be testing your water quality with a liquid testing kit on a regular basis or you have no idea whats going on and be able to correct it before problems worsen - its the very first thing you should do if you notice any sort of problem.

Lol! Thanks Gilli....I always thought it meant "in my hobby observations"
I guess both work.

 

[gforce17]

I worked in a world which used acronyms all the time and it used to drive my wife mad when I said something like 'I'm off to HTCF now'. I know how she felt now. lol (oops done it again)

What Gilli says rings true with me from my limited reading. You wouldn't put cold and tropicals together.

 

[N0body Of The Goat]

My two top suspects would be either aggression from the Platy or a sizeable ammonia/nitrite spike