40 gallon / 155liters - silent cycle - green or red? Stocking suggestions please!

Hello everyone and greetings, I hope you're doing well! Happy to be here and join the community! Thanks a lot for all the info already posted that has been keeping me entertained while waiting for the tank to cycle

Like so many others, I had fish when I was a kid and now I'm in the process of setting up an aquarium for me and my kids. I've done some reading, and some work and I'm looking for feedback.
I'm doing a silent cycle with plants.
I have a 155liter / 40 gallon aquarium, 80x40x50 cm or 31x15x19 inches and I'm running a Tetra ex 800 plus external filter with it.

7-oct-2021, original setup:



22-oct-2021, today:




Water parameters:
Tap water hardness from water company: 7.8 dH
I'm using JBL AquaTest Pro, which I'm fairly happy with for all tests except pH where given the shade of green I'm not sure if it's 7.5 or 8. I've used 8 in the table below:


I've added Tetra SafeStart bacteria on 7-oct and I've done a 15% water change on 14-oct and I'm planning to do another one tomorrow.

Given all this and plant growth do I get green light for stocking? I'm thinking clean up crew at this time... I can see white algae, brown algae, green algae... I'm thinking that should keep them busy if it's safe to add some now.

I would also like feedback on stocking options please. I'd like to keep the tank around 23 Celsius / 73 F and I'm thinking:

Pearl Gourami 3
Cardinal or Ember Tetra 12
Cherry Shrimp 8
Otocinclus 3 (I don't like corys and I can't remember the name of the brown sucker mouth fish I had when I was a kid, similar to bristlenose pleco somehow but without the bristles)

Does this work? I'm open to suggestions. I don't want live bearers as they multiply too much for me, otherwise I would go with some moly/xifo which I like.

If I get green light, I'm thinking to add a few Cheery Shrimps this week.

Thanks a lot for your time reading and your feedback!

Have you been adding ammonia to the tank regularly to feed the cycle?
Based on your readings, I don't think your tank is cycled.

Also, I would wait to add the Cherry shrimp. They graze on biofilm, and your tank is too young to have enough biofilm to feed the shrimp well. Some suggest waiting 6 months to add shrimp, but you could probably add them sooner than that. I would add the tetras and gourami first.

I'm certain the Pearl Gourami will eat the Cherry shrimp. I wouldn't suggest keeping both of those together.

I would get more Otos. They're schooling fish in the wild (like small tetras), and they behave and look much better in a large group. You definitely have room for more too. Here's a video showing the collection of Otos. You can see they're in a tight, massive school. Like the Cherry shrimp, Otos feed on biofilm and algae. I would suggest waiting awhile to add them.

The OP isn't doing a fishless cycle they are doing a planted cycle, other than that I would agree with @threecharacters.

I would add some (not all) of the fish first and be conservative with the feeding until you have tested a few times. I would also consider using a supplement such as flourish to help the plants outcompete the algae. And you will want the tank good and dirty before adding any Otos. I only have two Otos because I don't want them to run out food, and they seem confidant, but I think that's because I have cories and I read once that they superficially resemble each other because they tend to hang out together in the wild.

Your pH isn't ideal, but as the hardness is just about ok, you might be alright. Is the water too soft for guppies?

Sorry, I have asked more questions than I answered....

For a planted cycle I would say you are ready - but I have no experience there; I totally confused myself by getting bored and planting plants during a fishless cycle...

Thank you @threecharacters @Myraan

I am indeed doing a planted cycle, sorry if I wasn't more clear about it, following instructions here: https://www.fishforums.net/threads/planted-silent-cycling.470400/
I have not added ammonia, I've added some fish food at start and let it rot. I can add more bacteria together with the fish if that makes sense.
I should have also mentioned that I have added plant fertilizer (does not contain ammonia) after the partial water change on 14-oct. I'll add more after the water change I'm planning tomorrow. I don't have a lot of algae, certainly not taking over the whole tank, but it's there.

I'm certain the Pearl Gourami will eat the Cherry shrimp. I wouldn't suggest keeping both of those together.

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Sad to hear about Pearl Gouramis eating the shrimps... I was hoping that if shrimps go in first and Gourami last, they won't claim the whole tank for themselves and kill/eat the shrimps in the process... I'll replace the shrimps with more ottos in this case... very nice video - that was very surprising to see!!!

Is the water too soft for guppies?

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It's just that I don't want guppies because they breed like crazy and I don't find them particularly interesting. In my head I associate them with chicken

For a planted cycle I would say you are ready

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Then maybe I'll add some tetras, sounds like a better choice to start. Would 6 be a good number to start with? And then add 6 more in 2 weeks if all goes well?

One more note about hitch hikers: I have 4 bladder snails and 2 unknown, much slower growing ones. I'm planning to remove all of them if I can before the tank reaches 3 weeks to avoid an explosion of snails. They have been hard at work circulating the tank and eating algae and pooping everywhere
Here's a picture with 2 suspects:



PS: any more stocking suggestions? Perhaps a different gourami that would do well in 23 Celsius and not eat the shrimp?

Thank you!

Sounds good.

Yes I don't like that JBL pH test either - but that is because it is a wide range one. They sell refills of the two shorter range tests if that helps. I'm using my hold API pH test at the moment.
(If you buy the JBL tests separately and not just as refills you will get spare test tubes and maybe a viewing block which may be helpful if you have the kit with just a few bottles and you want to check the tap water too)

If you are worried about lack of clean-up crew - the snails might just be your saviour to be honest.

Definitely add the shrimp last.
You can increase the necessary biofilm by adding extra bottled bacteria, (which will give your cycling a boost), and some leaves and alder cones. If you're unfamiliar, then this might help.
I actually think your shrimp will be okay with the Pearl gourami. Mine are certainly safe with my Dwarf...even the little baby shrimplets, although any fish would have to be extremely quick to catch them, as they appear to have quantum physics sewn up and can instantly teleport from one part of the tank to another.

@Myraan great tip, I'll order the individual refills and use with the rest of the kit! Thank you!

@Bruce Leyland-Jones I'll get another bottle of bacteria and add it with the fish. Thanks for the link and info, alder cone sounds very good to me, I'll look into it some more!
And excellent news on the shrimp... I'll try to add them second to last, so before the gourami, assuming I stick with the current ideas/plan.

In fact, now, I'm contemplating the following :

Pearl Gourami 3
Cardinal Tetra 8
Ember Tetra 8
Cherry Shrimp 8
Otocinclus 3-6

I think I have the room for all of them and then definitely stop here. I don't want to overcrowd, I'd prefer the opposite to be honest.

I'm thinking to start with 6 Ember Tetras as they seem the more hardy of the two and slowly build from there.

The GH at 8 dH (7.8 is close enough to be 8) it is moderately soft/moderately hard. Fish listed in post #8 are soft water but in this range so no problems there.

Shoaling fish like the tetras and otos are best in larger rather than smaller groups. Given the tank space (limited but not crowded as a 20g would be) I would do larger groups and perhaps fewer species though the latter is not really an issue yet even with more of each of these species. A group of 10-12 cardinals, and 12-15 embers. Pearl Gourami are OK if you can get one male and two females, or maybe three females [see issue below though]. Otos, agree to hold.

You have no substrate level fish (otos are upper water like all the others). I assume from the photos the substrate is not sand so cories should not be considered.

With any shoaling species, it is always best to add the entire intended group together at the same time. They settle in much faster with less issues. Those species that might be hierarchal will be better established if added together; late comers are not always welcome, depending upon the species. If those plants are growing, which from the two photos they seem to be, you could never realistically add too many fish to have ammonia issues, the faster-growing plants simply assimilate it rapidly. You do not need any biological additive, the plants are best. You might want to add some floating plants though, as the fish selected need them. Especially gourami, there must be a reasonable cover of substantial floating plants like Water Sprite, Water Lettuce, or Frogbit. These will aid the tetras by providing shade (cardinals actually have a light phobia), but are indispensable for gourami.

@Byron I appreciate all the help, thank you.

I could go with just one type of tetras, I like the Cardinals more, I'm a bit worried as they may be more sensitive, at least on paper.

For the gravel part of the substrate I have 3 types of gravel:
4-7mm
2-3mm
1-2mm
In general I have the 1-2mm type on top (4-7 and 2-3 under), and then I dropped just a bit of the 4-7 larger ones for looks/variety

For floating plants I had some duck weed but didn't work well. I tried to make a circle out of tube to keep it still but I failed (tube not thick enough) as I move the water surface with the filter stream. I have a couple of Egeria najas that are now reaching the water surface. As these are growing so fast, I think they'll soon provide the cover. If that's not good enough then definitely, I'll add more, one or even all 3 suggested (Water Sprite, Water Lettuce, or Frogbit).

I'm updating the list and I will research on substrate level fish that would be suitable - please send over suggestions.

Pearl Gourami 3 (1 male, 2 female )
Cardinal Tetra 15
Cherry Shrimp 8
Ottos - on hold

I understand that I should be good and it's better to add all the cardinals as the next step.

Thank you!!!

Cmdr_DASh said:

@Byron I appreciate all the help, thank you.

I could go with just one type of tetras, I like the Cardinals more, I'm a bit worried as they may be more sensitive, at least on paper.

For the gravel part of the substrate I have 3 types of gravel:
4-7mm
2-3mm
1-2mm
In general I have the 1-2mm type on top (4-7 and 2-3 under), and then I dropped just a bit of the 4-7 larger ones for looks/variety

For floating plants I had some duck weed but didn't work well. I tried to make a circle out of tube to keep it still but I failed (tube not thick enough) as I move the water surface with the filter stream. I have a couple of Egeria najas that are now reaching the water surface. As these are growing so fast, I think they'll soon provide the cover. If that's not good enough then definitely, I'll add more, one or even all 3 suggested (Water Sprite, Water Lettuce, or Frogbit).

I'm updating the list and I will research on substrate level fish that would be suitable - please send over suggestions.

Pearl Gourami 3 (1 male, 2 female )
Cardinal Tetra 15
Cherry Shrimp 8
Ottos - on hold

I understand that I should be good and it's better to add all the cardinals as the next step.

Thank you!!!

Click to expand...

OK, a couple issues remain. Floating plants...for gourami the substantial plants really are mandatory. Gourami spend their time browsing among the root masses of floating vegetation. Duckweed does not provide this, only substantial plants like the three mentioned. I really would not consider gourami until there are some growing floaters.

Nothing wrong with the gravel, it is just that many consider cories for substrate fish (they are so cute and comical!) and they must have fine grain and smooth sand, as they filter feed. But other fish that do not have this need are worth considering...I just can't think of any, but I'm sure some exist.

You are going to have major problems if you don't get your pH down to around 6.5, That substrate doesn't look suitable to run any Tetras or acid loving fish.

Cmdr_DASh said:

I have a couple of Egeria najas that are now reaching the water surface. As these are growing so fast, I think they'll soon provide the cover. If that's not good enough then definitely, I'll add more, one or even all 3 suggested (Water Sprite, Water Lettuce, or Frogbit).

Click to expand...

For a quick growing floating plant, with nice, long, gourami friendly roots, check out Salvinia auriculata. This isn't as contagious a floater as, say, duckweed and yet grows fast enough to do what you want it to and to keep all of your tanks suitably covered.

itiwhetu said:

You are going to have major problems if you don't get your pH down to around 6.5, That substrate doesn't look suitable to run any Tetras or acid loving fish.

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I have ordered the more precise pH tests to figure out what it really is (I've only used a wide range test and I'm not certain about the shade)

Bruce Leyland-Jones said:

For a quick growing floating plant, with nice, long, gourami friendly roots, check out Salvinia auriculata. This isn't as contagious a floater as, say, duckweed and yet grows fast enough to do what you want it to and to keep all of your tanks suitably covered.

Click to expand...

I was indeed eyeing Salvinia but sadly it was not in stock. I ordered Ceratopteris thalictroides and Limnobium laevigatum for now. I still have lots of time to add it later, I'm not looking to add the gourami before all is good and ready for them.

I have Salvinia, lovely plant, but not what you want with any gourami. They need the more substantive root systems of the earlier mentioned species.

On the pH, there is no problem sorting out exactly what it is, but no not under any circumstance considering messing with it. The pH is very closely tied to the GH and KH. Given the numbers for these, the pH is likely going to stay pretty much where it is. However, pH in tap water can be very different from in the tank.

When you test pH in tap water, let a glass of fresh tap water sit 24 hours, then test. This will give you a more reliable reading. Tank water does not need this step, unless it is just filled. The biological processes in an aquarium will impact water chemistry naturally, and there is no value in trying to force them otherwise. Let the system stabilize so you know what you are dealing with.