A lot of species from the DLC can breed, but only three can give you hybrids : Guppy, Amazonian angelfish and Discus. On their requirement page, this is represented by a DNA icon.

Hovering over this icon with your mouse and the game will show you two infos :
- Breed two fish with the same color gives you the possibility to get a color mutation
- Breed two fish with different colors and you may get a pattern mutation, but also bigger probability
to get a color mutation.

I didn't dig into games files, but only bred hybrids during several hours. All the infos I give you come from my experience.
For now you may wonder "is there a mendelian genetic system, with genealogic trees ?" and I will answer you : I don't know. And honestly, you don't really need to know to successfully get all hybrids.
Same with mutations rates, I don't have exact numbers but don't worry this is not a ultra low rate. You can expect mutations at almost every breeding event if the parents have different color and pattern.

Now i'll give you the list of hybrids per species, with screenshots to show them, and some tips to make it easier to hybridise them.
Ther is also a part including tips from other players, because it's always better to have various point of views and methods !

Disclaimer time : I'm not a native english speaker so forgive me if I commit some english mistakes, or for the exact hybrids english names !

The Guppy is the first hybridisable fish you unlock, and like in real life, it breeds really, really fast !

COLORS :

We have 7 possible colors variations :

Regular (brown, the one you can purchase)
Emerald (green)
Scarlet (red)
Aqua (light blue)
Fuchsia (pink)
Lilac (dark purple)
Saphhire (dark blue)

PATTERNS

We have 4 possible patterns variations :

No pattern (the one you can purchase)
Cobra (black stripes on the caudal fin)
Inked (large black spots on the body and the caudal fin)
Leopard (black spots on the caudal fin)

All colors can exist in all patterns, so we have a total of 28 differents guppies !

Scarlet and Sapphire










Fuchsia and Aqua










Emerald and Lilac










Regular-colored Guppies with a pattern get their own color : Cobra is Black and brown, Inked is orange and leopard is black and yellow !












Get all hybrids Guppies


As they will reproduce fast, the best way is to first randomly breed them.
First, build a tank big enough to house several guppies, and fulfill all their needs to get them breeding.
When you get your first fry, put them in another tank without adult fish, correct heating and high water quality. This will maximise survival rate, more guppies will grow into adult and that means more potential mutations. don't forget floating plants and food, fry need to eat !

When they grow into adults, take a look ! first you will get only color mutation, I only get Emerald and Scarlet guppies by breeding regular ones. Take all mutants and put them in the first tank, you can also sell some regular guppies.

Now, you can continue this process trough several generations, with differents colors you will get patterns soon, and more colors, patterns etc...
After some time, sort your fish by color (using multiple tanks) and find out what you still don't have, and work with pairs.
For example, you miss only Cobra Sapphire and Leopard Lilac ?
Build two small tanks, Put one no-pattern Sapphire and one regular Cobra in one tank, same with one no-pattern Lilac and one regular leopard in the other !

Theory

I've noticed something, it may be wrong, this is only suppositions from what I observed !
It looks like there are 4 color categories ("generations") :
1 is regular guppy
2 are Emerald and Scarlet
3 are Aqua and Fuchsia
4 are Sapphire and Lilac

I noticed that I only got Emerlad and Scarlet when breeding regular guppies, and never got Sapphire or Lilac before Aqua and Fuchsia.
So we have three possibilities : I was unlucky two times with Sapphire and Lilac (campaign 3 and sandbox), or colors don't have the same mutation rate, or you need to breed some colors first to get some others colors.

As nothing this is only a theory, don't take it too seriously. But I'm interested if you want to share your experience about it !

This one is a little different because we don't have a mix with colors and patterns, mutations result only in differents skins !

SKINS :

We have 6 possible skins :

Regular (with some dark stripes, the one you can purchase)
Blushing (white with red cheeks)
Marble (with a lot of dark stripes)
Golden (entirely gold)
Koï (white with a big red spot on the head and some littles black spots)
Black lace (entirely black)


Regular










Blushing










Marble










Golden










Koï










Black lace












Get all hybrids Angelfish :

You will need a tank where breeding needs are fulfilled for your fish. Put some Angelfish in, but not too much, they are territorial ! They beed moderatly fast, and you can accelerate the process by adding more verticals surfaces in the tank.

When you get spawn, put them in another tank without adult fish and high water quality, to maximize the survival rate. Spawn will hatch and become fry. Don't forget the verticals surfaces and food they need !
Once they grow, select all the new skins you get abd breed them in the first tank. Try to breed fish with differents skins !
Don't hesitate to get rid of regular ones or build a new tank, otherwise the territorial trait will bother you You can even build multiple tanks to easily pair up fish with skins you want to cross.
Keep also in mind that after breeding, they have a cooldown of a few day before they can breed again.

Theory :

I have the same "generations" theory I had with guppies :
gen1 = regular
gen2 = Blushing and Marble
gen3 = Golden
gen4 = Koï and Black lace

It's because I only get regular, Blushing and Marble when breeding regular ones
I don't remember how I got Golden, but it was never with two regular parents
I never got Koï and Black lace before getting Golden

Of course those are only theory, I was maybe just unlucky or Koï and Black lace are just rarer ! If you want to share your experience about it, I'll be happy to read you !

This one is the hardest fish of the three to hybridize, because it is capricious. But first, take a look at all hybrids you can get with it.

COLORS :

We have 3 possible colors variations :

Regular (pink, the one you can purchase)
Blue
Yellow


PATTERNS

We have 4 possible patterns variations :

No pattern (the one you can purchase)
Spotted (paler body color and deeper colored spots)
Striped (even verticals black stripes)
Heckel (vertical black stripes, some of them are thicker)

All colors can exist in all patterns, so we have a total of 12 differents Discus !

Regular










Blue










Yellow










Spotted










Blue spotted











Yellow spotted










Striped










Blue striped











Yellow striped










Heckel










Blue Heckel












Yellow Heckel












Get all hybrids Discus

As you can see, we don't have that much hybrids compared to guppies. BUT it will take a longer time to get time all, because Discus are way harder to breed.
The pair need to be alone to breed, so you have to build several tanks (I had 10 couples so 10 tanks). Tanks have to be big enough because Discus is a territorial fish.

Be careful, if you have a lot of discus, you need staff members with very high feeding level becaus they are hard to feed and even require supplement.

Fulfill all fish needs (floating plants and verticals surfaces) and wait after them to breed, this is longer than other fish.
When you get spaw, don't put them in another tank and keep the parents, because fry need to be fed by at least one of its parents ! (they also need to be fed by your staff).

after you took all the precautions mentionned above, you just need to wait until fry grow into Discus. Sadly, their natural survival rate is quite low, so put a lot of filters to get at least 105% water quality ! even with this water quality I lost a few fry (it's rare but can happened)
So you will also need High level staff in fixing if you have a lot of discus tanks (using pumps will help you to not dispatch your filters everywhere).

Keep in mind that after their fry grow into adults, parents need to wait several days to be able to breed again.

Your first goal is to get blue and yellow Discus (you can get both from two regular parents), then you will have to cross different colors to get new patterns (you should get all of them no matter the parent's colors, they only need to be different. However some players say they only get Heckel Discus by crossing Spotted and Striped parents)
And when you get patterns, cross discus with different colors and patterns to maximize your odds of getting all of them !

The real difficulty is not about finding new colors and patterns, this isn't that rare. The real difficulty is that Discus breeding is slow and require a lot of attention and patience.

It's good to mention that the way I used to get hybrids is only my method, and you may want to do it otherwise

That's why, after some feedbacks on this guide, I decided to put in some other players methods (with their approbation !)
If you want to share your tips, you can also do it in the comment section of this guide !
It will enable you to choose your favorite way to breed hybrids, or even mix and improve our methods depending on how you like to play, etc...

We have some tips to breed Guppies and Amazonian angelfish, by krishnath.dragon :


I've found it is better to do the following (note, you'll need a heck of a lot of space to do this).

Guppies:

1. Build a number of 2x2 basic tanks (at least twelve, but any number of tanks divisible by four will do.)
2. Connect the tanks with pumps to save on hardware. I suggest connecting the tanks two at a time with large pumps (the 2x1 sized one). Add a Power Filter, and when available, a nitrate reactor to each pump.
3. Fill all the tanks with floating plants. Guppies need these to breed.
4. Select two of the tanks and put a pair of common guppies in each. Once they've bred and the fry have been born, move the fry to another tank and mark it with their parentage.
5. Once the fry are adults, find any hybrids and sort them into different tanks. Common guppies, you can either sell or put into a larger "holding" tank without floating plants to prevent breeding.
5a. If you end up with hybrids that are two types (say Aqua Leopard for example), and you want to "purify" the line (so you end up with pure leopard or pure aqua to follow up on the above example), pair it with a common. Breeding two of the same color together will nearly always produce offspring of the same color. It is the same with patterns.
6. Keep breeding, your goal is to make at least one "pure" of each color and of each pattern.
6a. If you lack a color, try breeding two other colors together. For example, breeding a sapphire with a scarlet increases your chance of getting a violet.
7. Once you have a pure of each color and each pattern, all you need to do is match the color you want with the pattern you want and breed them together. The resulting offspring has a pretty high chance to be your goal.

Amazonian Angelfish:

By the time you get the Amazonian Angelfish's breeding substrate, you should have access to RO machines, which makes it a lot simpler.

1. Build (at least) two 3x3 lagoon tanks.
2. To each Lagoon tank connect a power filter, a nitrate reactor, and an RO machine (if you have strong enough variants of them, connect them to both tanks with a large pump as with the guppy tanks).
3. Decorate both tanks to the angelfish's liking, make sure to include the breeding substrate.
4. Add one pair of Amazonian Angelfish to each tank. But only one pair.
5. Build a large holding tank while you wait for them to breed. Make sure to *not* put any breeding substrate in the tank.
6. Once they breed, let them be. No need to move eggs or fry. Angelfish practice brood care and keeping the parents with the young increases survival rate.
7. Once the fry reach adulthood, move the resulting angelfish to the holding tank.
8. Build additional lagoon tanks as space permits to breed any resulting hybrids.


I don't currently have any advice on the Discus, as I haven't gotten that far yet. But the above is a lot more effective than just keeping all of them in one tank and relying on pure chance. Also, as a final note, water quality is king when it comes to the survival rate of fry, and boosting it as much as possible is a must.

And that's all I had to tell you !

I hope this guide will help you, and if you have some suggestions or corrections to improve this guide and kill false informations, don't hesitate to say it ! (especially about my theory with generations, even if I mentionned two time that it is absolutely not 100% sure)

Maybe you also want me to talk about hybrids from mods such as clownfish and swordtail ?

And who know, maybe one of you discovered a rare hybrid wich is not on my guide !

Tank you for reading !