My new aquarium(freshwater)

[Swartz44]

Hi all. Im new to this forum but not new to fish aquariums. I had multiple freshwater aquariums when I was in my teens and twenties. Anyway I'm 44 yrs old now and just started a 20 gallon aquarium again. Ive always had: angel fish, sword tails, guppies, mollies barbs and tetras. Im somewhat knowledgeable on water quality and things of that nature(but its been about 20yrs since my last aquarium. I setup my aquarium on 9/31/20. I let it run without any fish for about 1 week. In the past 3-4 weeks I've added 2 gold dust mollies(first 2 fish) then a male & female guppy(male died about 2 weeks later) 1 red tailed black shark, 2 female black mollies, 1 new male guppy guppy to replace the one that died. Anyway I have 8 fish in a 20 gallon aquarium. Im pretty much done adding anymore unless I see a nice male and female swordtails. Im pretty good at purchasing fish healthier and looking for any fish issues before purchasing any. My water is alittle on the alkaline side at 7.4-7.6ish. Ive been trying to slowly lower it with ph down to a more neutral setting at 7.0. Anyway I did a nitrite, nitrate & ammonia test lastnite and nitrite-nitrate were perfect but was alarmed to see my ammonia was slightly up. I have done one 25% percent water change(last saturday) since september 31th when I setup the tank. Im alittle baffled by the ammonia reading(ive never issues with this with my other tanks). Is there a possible issue that my aquarium hasn't fully fully cycled yet? How after would you recommend i change the filter cartridge in my bio wheel outside filter? My fish seem to be pretty much fine except for male guppy that died & the one female gold dust Molly seems to be somewhat out of it(staying in one spot at times with some heaving gill movement & then at times seems perfectly fine and eating.

Any help is greatly appreciated

 

[AilyNC]

Is the Molly pregnant? Kinda sounds like actions when they drop fry.

Sounds like tank isn't cycled.

Cycling Your New Fresh Water Tank: Read This First!

Cycling Your First Fresh Water Tank What is Cycling and Why is it Important? Fish waste, and especially fish breathing, plus uneaten food and other organic matter breaking down in a tank all produce Ammonia. This can quickly become toxic to fish if it is allowed to build up to any measurable...

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Best to deal large water changes to get rid of the ammonia. Daily until your tests show Ammonia 0, Nitrite 0 & Nitrate 0.

Rescuing A Fish In Cycle Gone Wild - Part I

RESCUING A FISH IN CYCLE GONE WILD Part I If you are reading this it means you have tried to cycle your tank using fish and have run into problems and don’t know what to do. Before we begin to discuss the potential solutions, we would like to make it clear that we do not recommend to...

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[Jamesthecat]

Agree with the big water changes - your basically diluting the amount of ammonia and giving the helpful bacteria chance to catch up. Carefull changing the filter media unless your just giving it a quick rinse in tank water

 

[utahfish]

Hi all. Im new to this forum but not new to fish aquariums. I had multiple freshwater aquariums when I was in my teens and twenties. Anyway I'm 44 yrs old now and just started a 20 gallon aquarium again. Ive always had: angel fish, sword tails, guppies, mollies barbs and tetras. Im somewhat knowledgeable on water quality and things of that nature(but its been about 20yrs since my last aquarium. I setup my aquarium on 9/31/20. I let it run without any fish for about 1 week. In the past 3-4 weeks I've added 2 gold dust mollies(first 2 fish) then a male & female guppy(male died about 2 weeks later) 1 red tailed black shark, 2 female black mollies, 1 new male guppy guppy to replace the one that died. Anyway I have 8 fish in a 20 gallon aquarium. Im pretty much done adding anymore unless I see a nice male and female swordtails. Im pretty good at purchasing fish healthier and looking for any fish issues before purchasing any. My water is alittle on the alkaline side at 7.4-7.6ish. Ive been trying to slowly lower it with ph down to a more neutral setting at 7.0. Anyway I did a nitrite, nitrate & ammonia test lastnite and nitrite-nitrate were perfect but was alarmed to see my ammonia was slightly up. I have done one 25% percent water change(last saturday) since september 31th when I setup the tank. Im alittle baffled by the ammonia reading(ive never issues with this with my other tanks). Is there a possible issue that my aquarium hasn't fully fully cycled yet? How after would you recommend i change the filter cartridge in my bio wheel outside filter? My fish seem to be pretty much fine except for male guppy that died & the one female gold dust Molly seems to be somewhat out of it(staying in one spot at times with some heaving gill movement & then at times seems perfectly fine and eating.

Any help is greatly appreciated

Most those fish get too big for a 20 gallon.
Red tail sharks get about 6 inches and are semi aggressive they are a long bodied fish and strong swimmers that need long tanks they are also a softer water fish where as mollies are hard water fish. Mollies also get pretty big and need more room than a 20 provides.
If anything id re-home the shark as not only is it not compatible with the mollies and guppies but 20 is way to small for a red tail sharks.
Good luck here's a profile by seriously fish. Notice the recommended hardness for mollies is 15-30 DGH which is much too hard for red tail sharks. Also recommend tank size for mollies is 36 inches long which would be closer to a 30 gallon or 40 gallon.

Poecilia sphenops – Short-finned Molly/Black Molly — Seriously Fish

www.seriouslyfish.com