What to stock in 42 gal tank

[TTanks2]

New here, only ever had a betta. Just set up my first 42 gal tall tank. I’m looking for advice on what I should stock it with. Planning on cycling the tank I while I create a stocking plan. But I have no idea where to start.

My tank is in the living room, and I want it to be a point of focus for my young children. So looking for it to be lively and educational. It is a dirted tank, capped with 2 inches of fluorite red gravel, and is planted. So I’d want to avoid anything that’s going to breach my cap or uproot my plants.

 

[Colin_T]

Hi and welcome to the forum

What are the tank dimensions (length x width x height)?

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What is the GH (general hardness), KH (carbonate hardness) and pH of your water supply?
This information can usually be obtained from your water supply company's website or by telephoning them. If they can't help you, take a glass full of tap water to the local pet shop and get them to test it for you. Write the results down (in numbers) when they do the tests. And ask them what the results are in (eg: ppm, dGH, or something else).

Depending on what the GH of your water is, will determine what fish you should keep.

Angelfish, discus, most tetras, most barbs, Bettas, gouramis, rasbora, Corydoras and small species of suckermouth catfish all occur in soft water (GH below 150ppm) and a pH below 7.0.

Livebearers (guppies, platies, swordtails, mollies), rainbowfish and goldfish occur in medium hard water with a GH around 200-250ppm and a pH above 7.0.

If you have very hard water (GH above 300ppm) then look at African Rift Lake cichlids, or use distilled or reverse osmosis water to reduce the GH and keep fishes from softer water.

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You want to change the light colours so it looks white. You can have red, green, blue, yellow and white light but the colour should appear white. Fish don't like blue or purple light on its own.

If you have live plants, they also need red, blue, green and white light.
For plants, the red & blue light should be even. Green can also be even and white can be added to make it look white.

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Some dirt substrates can continue to release ammonia for months so monitor the ammonia levels and if you have ammonia readings for months, it is probably form the substrate.

 

[TTanks2]

Hi! Thank you, my tank measurements are 36” x 12” x 24”.

I’m attaching an image of our water report. I have ordered a GH and PH test kit as well!

Thank you for the heads up on the lighting! I am currently using glow lights for the plants that I had lying around while I cycle! So that just reaffirms what I told my husband - we need to upgrade our tank lighting

Do you know of any resources that could help guide a person to appropriately stock their tank?

 

[Colin_T]

I’m attaching an image of our water report. I have ordered a GH and PH test kit as well!

The water report seems to suggest you have a GH of about 150ppm, which is soft and would suit tetras, barbs, rasboras, gouramis, etc. However, it has a column called SMCL and I don't know what that means. It kind of looks like the range after the water is treated but could be anything.

The report says the pH is 7.2 but then in the SMCL column it is 8.5

The KH (alkalinity) is 410ppm, but in the SMCL column it is 300ppm.

The units MG/L is milligrams per litre, which is the same as ppm (parts per million).

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There are a few things in the water that concern me (barium & chromium and a few other things). A water filter should help remove some of these and make it safer for you to drink.

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Thank you for the heads up on the lighting! I am currently using glow lights for the plants that I had lying around while I cycle! So that just reaffirms what I told my husband - we need to upgrade our tank lighting

Most new LED light units have a range of different coloured LEDs and can be programmed to have different colours and intensities. If you have fluorescent globes and want to keep the light unit, get daylight globes with a 6500K (K is for Kelvin) rating. These can be used on their own or in conjunction with your current red globe.

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Do you know of any resources that could help guide a person to appropriately stock their tank?

https://www.seriouslyfish.com/
has info on different species of fish but you can also ask on here.

 

[Aiken Drum]

SMCL is the safe limit on contaminants in water.

 

[TTanks2]

Thank you all so much for this information. I am learning so much!

What’s everyone’s thoughts on have a community tank with the following?

Actually not going to do the bristlenose pleco. Can’t risk him ripping up my plants and breaching my cap.

 

[Colin_T]

What’s everyone’s thoughts on have a community tank with the following?

Actually not going to do the bristlenose pleco. Can’t risk him ripping up my plants and breaching my cap.

Peacock gudgeons should be kept in a single species tank or with other small slow moving peaceful fish like Pseudomugil rainbowfish or Iriatherina werneri (another small rainbowfish).

Serpae tetras are renown fin nippers and should not be kept with slow moving fish or fish with long fins. Most tetras should be kept in groups consisting of at least 10 (preferably more) individuals. These fish naturally occur in groups of thousands so even 10 fish in a tank is unusual for them.

There are a number of small peaceful red coloured tetras including the red phantom tetra, flame tetra, & ember tetra (more orange than red). There are cherry barbs that are small and quite peaceful. The males go red when breeding and the females are brown.

If you get gouramis, only get 2. Either get 2 females or a male and female. Most gouramis are nasty, pearl gouramis are usually peaceful. Avoid dwarf gouramis (Colisa lalius) and any of their colour forms. These fish are regularly infected with the Gourami Iridovirus and or Fish Tuberculosis (Fish TB), neither of which can be treated. Pearl gouramis are usually free of these diseases.

All gouramis and Bettas like to have some floating plants to hide under. Floating plants also benefit tetras and catfish by providing shade. Water Sprite (Ceratopteris thalictroides/ cornuta) is one of the best floating plants for aquariums. If it grows too well, you can plant them in the substrate and they grow there.

Mystery Snails and Corydoras are fine with most fish. Don't keep Corydoras with loaches. You haven't mentioned loaches but I am just mentioning it now in case you see something you like. You either have loaches on the bottom of the tank or Corydoras, but not both.

 

[TTanks2]

What’s your thoughts on Congo Tetras?

And are there any species of goby fish that I can keep in a community tank like this?

So I’m thinking a mystery snail, 6-10 panda corydoras, 10 or so tetras (maybe Congo or one of the ones you mentioned), and then 2 female Pearl gouramis.

Or do you have any recommendations for a fun tank idea? Since I literally haven’t put anything in here yet, I could do a species only tank as well. I just want to make sure I set it up to be engaging and fun to watch!

 

[Colin_T]

Congo tetras need a tank that is at least 4 foot long and preferably longer (6ft+). They are active fish that can stress slower moving fishes simply due to their activity.

Most gobies come from hard or brackish water and need a bit of salt. They do best in shallower tanks (12-18 inches high) without other fish that will steal all the food
Tetras, gouramis and Corydoras come from softer water without salt.

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If you didn't have plant substrate I would go for a pr of Apistogramma cacatuoides, but they will dig a small depression when breeding and might cause the plant soil to come out.

I like black phantom tetras. You could get a group of black and red phantom tetras (8-10 of each) or some black phantoms and a group of flame or ember tetras. Add 2 gouramis and some Corydoras and you would have a nice peaceful community tank with some movement on the bottom (Cories), in the middle (tetras) and near the surface (gouramis).

 

[TTanks2]

Perfect! I think I’ve got a solid stocking plan! Thank you so much for the advice. I love the idea of the shoal of corydoras, a schooling group of tetras, and two gouramis.

Thank you so much for all of the advice.