Upside down catfish tank mate questions. Pet of the Month
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Wizard Lizard

Fish Fanatic
May 3, 2020
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So just a couple of things to get out of the way, this is my first post on this forum, idk what im doing, and im bad with words so please bear with me, ill try my best to be nice, polite, and clear. Also im not new to this hobby (couldnt find a better place to post this so if this is in the wrong place please let me know where to go) but am getting more serious about it, im no novice but im def no expert either. So ill prob know what your talking about and if i dont ill ask. Im also not the most confident in my abilities but i think ik enough to do good by my fish.

Now to my actual question, im hoping to get a new tank soon, ive been doing a lot of research to ensure things go well. I found that upside down cat fish fit perfectly with my theme (magic/mystical) but idk if they will be friendly to a few specific fish i also wish to get. These fish include ottos, pygmy corries, black neon and glass bloodfin tetras, celestial pearl and zebra danios, and endlers. Ive read they will eat smaller fish but are otherwise very peaceful, i believe this means fry/baby fish but seeing as they get near 4 inches id like to make sure before i buy. Thanks for the input in advance so i don't annoy you with continues thanks!
:hi: Welcome to TFF, and to this wonderful hobby.

You have listed fish species that should not be combined together for various reasons, so first I'll mention some background factors to setting up a community tank, which as you may know is one containing more than one species of fish.

First item is the water parameters, especially GH (general or total hardness), then pH. The KH (carbonate hardness or Alkalinity) is worth knowing as it directly impacts the pH but GH and then pH are the important parameters. The fourth is temperature, which we can more easily controlled with an aquarium heater, but here too not all "tropical" fish will be at their best in the same tyemperature so this too is a crucial factor.

The GH is the measurement of dissolved minerals, primarily calcium and magnesium, in the water. Each freshwater fish species has evolved over thousands of years to function in a very limited range when it comes to every aspect of its environment, from water parameters to the habitat features and other species. With respect first to the water parameters, we can consider three very general groupings here, namely fish species that must have soft or very soft water, species that must have moderately hard or harder water, and those species that may be primarily in either of these but in the middle so to speak. Considering the species you mention, you have some soft water fish (upside down catfish, pygmy cories, tetras, otos), while the Endler must have moderately hard water. Both danios are more in the middle but can work either side, depending. So the first thing to ascertain is the GH of your soource (tap) water. The pH tends to follow the GH so once we get the GH correct that is usually (with a very few exceptions) all we need be concerned about.

Temperature ranges for a species are available and each species selected must have the same basic range. None of the fish you mention has a noticeable variation from what we can consider the "norm" of mid to upper 70'sF (23-26C) but it is important to keep the temperature in mind.

The activity level of a species is the next important factor. From your list, zebra danios are very active swimmers (and with this usually goes a preference for lower temperatures), and this does not work with fish that are quiet and sedate. You have not included any that are especially sedate, but it is worth keeping this in mind should you consider other species. Gourami for example are not going to work with the danios.

The aquascape is another factor that must suit the individual fish. Danios need open space to swim, while the upside down catfish and cories are more browsers of surfaces. Unless the tank is quite large, this can be difficult to combine. Sand substrate is essential for cories, and as this is also suitable for most any other species it is thee best general substrate to go with in a tank. Plants to shade thee light, or provide browsing surfaces (the upside down catfish, the cory catfish) are important.

Some species are shoaling, meaning they must have a group. Numbers can vary, but this is a critical factor for the fish. Flow from the filter has to match what each species needs.

Last is temperament and compatibility. Yoou may wonder why I left this to last; the reason is that if the above aspects are not to the species' expectations, it does seriously impact the fish's health...first by causing stress and then leading to other problems, and in many cases the fish's temperament is thrown off balance by this, making them more aggressive or sometimes the opposite. All of which leads to further stress, and poor health.

So, the first thing to determine is the GH and pH of your source water, and the intended tank size--dimensions are needed more than volume, though this is also important.
Celestial pearl danios and zebra danios are a definite no no. Aside from the activity levels @Byron mentioned (CPD are sedate and timid), CPD are food sized for many other species and best kept in a species only tank or with other nano fish of a similar disposition.

Besides hardness you have not mentioned tank size. Many of the fish you mention need to be in large groups. Once we know the tank size and hardness we will be better placed to advise.
Sry for late response, i just woke up.

The water hardness in my area is actually very soft with minimal additives. As of last night actually i removed the zebra danios from my list.
The ph im aiming for is around 7. With a low hardness. Maybe a little bit of added calcium for plants and snails. Based off of the research ive done endlers and danios would be perfectly happy in soft water. Please correct me if I'm wrong. Ive just asked about the endlers and danios, everywhere and everyone ive asked has said they'd be very happy despite the water being softer.

The tank i plan to use is 75 US gal. Water temp id like to keep at 79F. Soft water with a little bit of calcium. Ph i hope to keep around 7. Might do a little bit of tannins but need to do more research on that with the fish i hope to keep. But as for the parameters, all the fish on my list fit well together based on my research. And i dont think ill be using sand. The substrate i hope to use is aquarium soil. Somthing that'll be soft on the fish and good for the plants.

Thanks for the input, if there is any other concerns please let me know, id really dont want a crisis or unhappy fish on my hands.
My whole idea is still a work in progress. A big reason why im here.
Endlers must have moderately hard or harder water, there isno way around this, they cannot function well in soft water. If you have soft water (what is the GH and pH of the tap water?) there are endless options for fish species that will thrive in it. Endlers will not.

Keeping pH around 7...this is fraught with risks. The place to start is the GH and pH of your tap water. If it turns out you can use this with fish that will thrive in such water, you will have far greater success for minimal effort, and that means much less risk of something going wrong and harming the fish. An aquarium operates according to the natural laws of biology and chemistry. It is always safer to use them and not try to change them. The pH is tied to the GH and KH, and you cannot alter pH without dealing with the GH/KH, depending what these are.

Plant substrate...this is not usually worth it. Depending what the substrate material is, it may need a cap of sand, or it may leech ammonia, or...whatever. Aquarium plants will grow well in an inert substrate.
So what would be a good alternative to endlers (not normal guppies) in your opinion. And as for the substrate i guess ill go with sand as i have experience with it. Ive never heard of such issues with aquarium soil but ive never used it personally.
If your water is soft that is great for all the fish you mention except endlers. You should still get a number and unit because soft means different things to different people. If you do have soft water fish in soft water it is best to add nothing. My water is extremely soft (GH=0, KH=0) with a pH of <5.5. My fish and plants thrive in this. I also have malaysian trumpet snails that have no problem with this, although I cannot keep fancy snails.

Trying to change your water parameters can be frustrating and expensive, and very often result s in dead or unhealthy fish. It really is best to choose fish that are naturally suited to your water.
Oh, i was actually hoping to get trumpet snails, good to know they dont really need the extra calcium. With that knowledge then i wont change water chemistry at all except maybe tannins like i said earlier but again ima have to do a lot more research on that as i have little experience with it. So that prob wont happen for a long time.

My areas parameters look like this based off what i could find, deosnt quite seem right but its what I got.

GH 12
KH 6.5
PH 7.5
All this is on the soft side but it doesn't quite look right but idk too much about this stuff, ill try to get some test strips or a test kit soon to make sure.
if that is all side things dealt with could i get an answer to the original question? don't wanna be rude, i really appreciate the help, but i do need my original question answered. thanks!
Oh, i was actually hoping to get trumpet snails, good to know they dont really need the extra calcium. With that knowledge then i wont change water chemistry at all except maybe tannins like i said earlier but again ima have to do a lot more research on that as i have little experience with it. So that prob wont happen for a long time.

My areas parameters look like this based off what i could find, deosnt quite seem right but its what I got.

GH 12
KH 6.5
PH 7.5

Is the GH of 12 measured in degrees or ppm or something else? Same question for KH though that is less relevant.
I believe it was ppm but i could be wrong.

There is a big difference depending which. A GH of 12 ppm is very soft, whereas a GH of 12 dGH is moderately hard. Considering the KH is given as 6.5, the decimal place would suggest dKH and not ppm for this, and one would expect the two (GH and KH) to be measured with the same unit.
Like i said im pretty sure its ppm, im hoping to get a test kit soon to be sure of all measurements.

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