# Aquarium stocking Question



## Zensational (May 28, 2017)

I keep seeing conflicting information on this, the rule that there has to be a gallon for every inch of fish. Now, I obviously don't want to overcrowd my aquarium, but I was wondering if I would be able to add a small school of hatchetfish, 3 most likely, and one small killifish. I've currently got 3 pom pom crabs and 13 dwarf shrimp, 7 nerite snails, 4 guppies, and 5 harlequin rasboras, in my 9 Gallon Fluval Flex, it's got a 3 stage filtration, sponge, bioring, and carbon, and my ammonia is always at 0ppm, and my nitrates are never above 5ppm, I do weekly water changes of 25% and spotclean the sand with airline tubing. It's a lightly planted tank with a few sprouts of dwarf sag, and a few stalks of Indian water sprite.

I was thinking that these additions would be okay, because I have lots of low laying inverts, and lots of mid level fish, and nobody that swims at the top of the water column.


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## RussellTheShihTzu (Mar 19, 2013)

Plug in specifics here: AqAdvisor - Intelligent Freshwater Tropical Fish Aquarium Stocking Calculator and Aquarium Tank/Filter Advisor. However, IME, you are already overstocked and under-planted.

Shoaling fish need a *minimum* of six for long-term health. You need to add at least one more Rasbora and would need six Hatchet Fish. If I'm remembering correctly from when I had them Hatchet Fish spend most of their time at the top so they would be really iffy with a Betta. Not necessarily because the Betta would chase them but that they would stress the Betta with their constant movement in his territory. They are very "busy" fish.


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## Zensational (May 28, 2017)

RussellTheShihTzu said:


> Plug in specifics here: AqAdvisor - Intelligent Freshwater Tropical Fish Aquarium Stocking Calculator and Aquarium Tank/Filter Advisor. However, IME, you are already overstocked and under-planted.
> 
> Shoaling fish need a *minimum* of six for long-term health. You need to add at least one more Rasbora and would need six Hatchet Fish. If I'm remembering correctly from when I had them Hatchet Fish spend most of their time at the top so they would be really iffy with a Betta. Not necessarily because the Betta would chase them but that they would stress the Betta with their constant movement in his territory. They are very "busy" fish.


I don't have a betta in this tank, it's a 9 gallon community, all my bettas are alone in their 2.6 Fluval specs. I have 9 inches of fish in 9 gallons of water. I also have inverts, but their bioload is so minimal, I didn't count them towards my stock levels. There's plenty of swimming room for everyone because the inverts all stay at the bottom, the current fish that I have already reside in the middle level, so I figured that if my tank could handle the bioload, I could add some top swimming fish. Is that not correct?


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## LittleBettaFish (Oct 2, 2010)

What species of killfish are you considering? Most killifish have a voracious appetite and will eat whatever fits into their rather large mouths. I would be concerned that they would pick at, or even eat, the shrimp. Some killifish species will also nip at fins or chase other fish in the tank. 

Personally, I don't think a 9 gallon tank would offer enough swimming space for a group (as already mentioned six is generally considered the 'bare minimum' when it comes to shoaling species) of Hatchetfish. Perhaps if they had been the only fish in the tank, but then you have both guppies and Harlequin Rasbora in there. 

The 'inch per gallon' rule is ridiculously outdated, and doesn't take into consideration other factors such as activity levels. For example, Zebra Danio are extremely active fish that require a large tank in spite of their small size. 

A better option may be a small group of Clown Killifish. They are a small and peaceful fish, and really my only concern would be that your other fish might harass them. 

As with all killifish they will also jump if the tank is left uncovered.


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## RussellTheShihTzu (Mar 19, 2013)

Zensational said:


> I don't have a betta in this tank, it's a 9 gallon community, all my bettas are alone in their 2.6 Fluval specs. I have 9 inches of fish in 9 gallons of water. I also have inverts, but their bioload is so minimal, I didn't count them towards my stock levels. There's plenty of swimming room for everyone because the inverts all stay at the bottom, the current fish that I have already reside in the middle level, so I figured that if my tank could handle the bioload, I could add some top swimming fish. Is that not correct?


Did you plug into Aqadvisor as suggested? What you can have depends on filtration and footprint. A nine-gallon, after allowing for substrate, equipment, plants, decor, etc., is only about seven gallons.

That aside, when considering fish you need to determine their minimum tank size requirements. Everything I've read, and remember, about Hatchetfish is they need a footprint equal to a 20 long aquarium: 30" x 12". They are too active for anything less although people force them into smaller tanks.

In your propsed tank with proper shoals you would have 16 fish; 17 inverts other than shrimp and nine Nerite. That's 42 critters in about seven gallons of water. Check Aqadvisor.


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## Zensational (May 28, 2017)

In the proposed tank a top the correct schooling levels, I'd have 17 fish, and only 3 inverts other than shrimp, and 7 Nerites. I checked out the website, and I couldn't figure out how to program my filter into it. So without my filter, it suggested 66% water changes weekly. Because my tank was stocked at a rate of 198%


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## RussellTheShihTzu (Mar 19, 2013)

What filter do you have? Find out the GPH (Gallons Per Hour) and plug that in instead of a particular filter. Click on "User Defined" under "Filter" and then how many GPH in "gUS." Did you plug in any filter at all or leave it blank?


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## Zensational (May 28, 2017)

RussellTheShihTzu said:


> What filter do you have? Find out the GPH (Gallons Per Hour) and plug that in instead of a particular filter. Click on "User Defined" under "Filter" and then how many GPH in "gUS." Did you plug in any filter at all or leave it blank?


I left it blank because Fluval doesn't specify what kind of filer the Fluval Flex uses.


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## RussellTheShihTzu (Mar 19, 2013)

61 GPH. Google "Fluval Flex filter GPS." Measure the actual tank portion. The dimensions given includes the filter compartment so is inaccurate when calculating stocking levels.

Edit: According to Aqadvisor with 7 Nerite, 6 Hatchetfish, 6 Rasbora, 4 Guppies and 16 Inverts other than Nerites your stocking level is 155% and you need to do one 66% water change per week or split and do two 41%.

I looked at your tank and it doesn't appear to have the 24"-minimum linear footprint the Hatchetfish need (from Seriously Fish). If the tank has at least a 24" length you should be okay.


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