Tropical Fish In Goldfish Water

[Sairbear_3]

Hi, this is my first post on this forum, and a fish keeping beginner.

I currently have a tank (Dims is L39in H13 D12in) with 4 medium sized goldfish.

The goldfish are being transferred to a bigger tank but I want to use the tank they are leaving to house some tropical fish (Guppies, Neon Tetra, Mollies) I know how to keep tropical fish, water temp, PH etc

My question is do I need to do a complete water change and gravel change or a partial water change?

Will the old goldfish water kill the tropical fish?

Will i need to replace the filter foam?

Thanks in advance

Sarah

 

[Jonnywhite]

I personally would do a 100% water change and wash the gravel out to it wouldnt kill your fish but may give them problems later on, and maybe buy a new filter sponge to be on the safe side or just clean it the best you can.

 

[the biffster]

i would do a 90% water change you could clean the gravel at the
same time i would just wash the old sponge out in old tank water
as replacing it might or would start the tank cycling again

 

[Wills]

I would just do a 50-60% water change and leave the filters as they are - make sure you add the new fish on the same day that you move the goldfish over - preferably a large section of fish you want as to avoid any cycling issues.

Wills

 

[waterdrop]

Agree with Wills. If the goldfish were healthy then there are no issues with either their water or gravel and the two species of bacteria that will have developed in the biomedia of your filter will be the same, giving you a set of filter media that is quite valuable to you for both tanks going forward.

It makes sense then that you will be way ahead if you develop a plan for making use of your bacteria for both tanks. You will want fully qualified biofilters on both tanks for both sets of fish unless you want to be changing a ton of water to keep the fish alive. The basic guideline to keep in mind that 2/3 of the volume of the biomedia (biomedia being the sponges or other media minus any mechanical or chemical media in your filter (fine floss is hte most common mechanical media and carbon and zeolite are examples of chemical media, others like sponge and ceramics are examples of biomedia) needs to stay with any existing fish you have to avoid mini-cycles where you get traces of ammonia or nitrite(NO2) because you have diminished or disturbed the existing bacterial colonies. Does that make sense?

If you are a beginner you probably have a mix of knowledge about the needs of both your coldwater and tropical tanks but you may not have experience in the various tricks to help divide and grow the biofilters and how to read the test results and know when the biofilters are ready (full cycled that is.) Cycling a cold water filter can be slower simply because the bacteria grow better at temperatures that are even higher than we keep tropicals. You definately may have several weeks or even a month or two of processes ahead if you want to do this right. I'm not necessarily the best at seeing the most efficient path to ending up with the two working filters and tanks, sometimes some of our other members are better at working this out, but I'm pretty good with reading the feedback of the tests and things. So hopefully some dialog will get going to help you.

~~waterdrop~~

 

[OldMan47]

I think WD is on the money here. Healthy goldfish means you have decent water quality and a well established biological filter. As soon as the water is warm enough for your tropicals, you should be able to add them to the tank. A light initial stock level in the converted tank and you could conceivably run both tanks using only your present bacterial population. You could also add the heater to the new larger tank, bring the temperature up to at least 75F and use the donated media from the goldfish tank to cycle the new tank. In little more than a week, you may well have a fully cycled new goldfish tank. At that point let the temperature in that tank fall back to room temperature and move the goldies. About a day later, you could probably have the tropical tank to at least 70F which is plenty for the guppies and mollies to do well. I tend to keep neons a bit warmer at around 77 to 78F.