[MC-134702] Fish spawned from buckets count towards the aquatic mob cap

Workaround

You can fix this issue for yourself by installing the attached

[media]

datapack to your world. This datapack sets PersistenceRequired for all mobs spawned by buckets to 1b, so that they no longer count towards the mob cap.

The bug

If there are at least 16 fish spawned from buckets anywhere in loaded chunks (that might be the spawn chunks, chunks loaded via /chunk, or chunks that players currently are in), no aquatic mobs (fish, dolphins, and squid) will spawn anywhere.

How to reproduce

Create a new superflat world (I chose "Redstone Ready") and change it so that it has biome minecraft:ocean
Run
```
/gamerule doMobSpawning false
```
Create a big aquarium at spawn
```
/fill ~ ~-1 ~ ~20 ~-21 ~20 water
```
Drop 16 salmon from buckets in there
Teleport to somewhere far away, for example
```
/tp 1000 56 1000
```
Check that all salmon still are there
```
/execute if @e[type=salmon]
```
Create a big aquarium there as well
```
/fill ~ ~-1 ~ ~20 ~-21 ~20 water
```
Run
```
/gamerule doMobSpawning true
```
Notice that no mobs spawn there whatsoever
Run
```
/kill @e[type=salmon,limit=1]
```
Notice that suddenly, there are many mobs spawning in that aquarium

How to fix this bug

Change the aquatic mob cap so that fish spawned from buckets no longer affect it.

Original report

As stated tropical fish and pufferfish are not spawning whatsoever in my main world. I created another world to see if they would spawn there and they spawned just fine. I have spent hours upon hours in my main world and I don't want to have to restart. Is there any way to fix this? I don't know if it's a factor, but I had to travel a fair distance from my spawn point to find warm ocean.

Linked issues

is cloned by 1

MC-148613 Aquatic mobs are not spawning / Fish spawned from buckets count towards the aquatic mob cap again Resolved

is duplicated by 5

MC-135539 Fish not spawning anymore Resolved

MC-135560 Ocean mobs stop spawning Resolved

MC-135590 Fish no longer spawn in ocean after collecting some in a bucket and releasing them in your own aquarium Resolved

MC-135881 Water mobs not spawning, If on spawn is aquarium full of nametagged fishes Resolved

MC-135940 Disappearing aquatic passive mobs Resolved

Attachments

ocean_reviver.zip

Comments 22

Uriel Salischiker 2018-07-24T11:25:59Z

Was your world migrated from 1.12.2 or its a new world in 1.13?

Mary Johannah Lane 2018-07-24T11:26:41Z

It's a new world from 1.13

Uriel Salischiker 2018-07-24T11:37:44Z

Try sleeping near the ocean so you spawn there, then kill all entities with /kill @e(that will kill you too), then check if tropical fish will start spawning

Mary Johannah Lane 2018-07-24T11:41:05Z

That worked. You are a life saver. Any idea what causes them to stop spawning?

Uriel Salischiker 2018-07-24T11:45:01Z

There is a limit of how many mobs can be in a world at the same time, looks like with all the exploring you did a lot of them spawned and they didnt despawn by the time you were in the ocean

12 more comments

Mary Johannah Lane 2018-07-24T11:47:35Z

Ahh I see, makes sense. Thank you so much.

Tom 2018-08-03T20:25:10Z

And that unfortunately kills all your passive mobs in any farms you have, all item frames in your world and the items in them despawn and minecarts/armor stands etc.

Is there a way to remove this mob limit becuase its extremely annoying.

Jamey Wynn 2018-08-04T17:59:35Z

The answer to this issue is don't release any fish from a bucket unless you use less then 15 of them. Anymore than that will stop all spawning of animals in the oceans. This includes dolphins, squid and fish. Apparently this is " Works as Intended".

Tom 2018-08-04T18:08:54Z

Well that sucks, what if some people want a huge aquarium with 50 or so fish in it? I guess Ill have to use spawn eggs if thats the case if they dont wanna change it.

Jamey Wynn 2018-08-04T18:24:10Z

Yea. I agree with you Tom. This does not make any since at all. I too had fish in an aquarium and a pond and realized later that they were not spawning anymore in the oceans. I guess until more complaints are made, the "Mods" are not going to do anything about it.

Torabi 2018-08-04T23:37:29Z

As far as I'm aware, persistent mobs are not supposed to count towards the mob cap. The ocean spawning rules seem to have a few bugs that have become consequential now that there are more water mobs than just squid.

Jamey Wynn 2018-08-05T00:56:29Z

Thanks Torabi for looking into this.

I too did not think they were supposed to count towards the mob count. I thought they were considered a named mob. I started naming the fish in a bucket at first, which gives the same results btw, then I did them without naming them as the wiki states that you do not need too.

Tom 2018-08-05T11:11:49Z

Does anyone think this issue will be looked at by the devs?, becuase as far as I am aware, the whole reason why they added fish buckets is so that people could have aquariums. However this bug is kinda preventing that from happening or being as good as it should be.

violine1101 2018-08-08T22:18:26Z

Alright, I looked further into this and apparently 16 fish spawned from buckets anywhere in loaded chunks are enough to not let any mobs spawn anymore anywhere in the world.

To test this I had two testing areas, one at spawn (always loaded), and one further away. In the spawn aquarium, I had 16 salmon (all spawned from fish buckets), I then went to the aquarium further away. No mobs spawned. I ran the command

/kill @e[type=salmon,limit=1]

there, and boom, multiple fish and squid spawned.

I edited this report so that it directly reflects that fact (over 15 fish from buckets in a world ⇒ no fish and squid spawning anywhere), I hope the reporter is fine with that.

violine1101 2018-08-09T10:29:59Z

I made a data pack that fixes this issue by setting PersistenceRequired to 1b for all fish spawned by buckets. Install the

[media]

datapack to your world in order to revive your oceans.

Max Smith 2018-11-28T22:26:48Z

This has been a problem since the update was released in July. How has Mojang not fixed this yet?

violine1101 2018-11-28T22:43:49Z

This has been fixed already. Over three months ago even.

Max Smith 2018-11-28T23:22:33Z

You mean with the datapack at the top of the page? I can't get that to work. Followed all instructions, as vague as they are, can't get fish back. Why are there no fish on my server?

violine1101 2018-11-28T23:27:48Z

No. This has been fixed in 18w33a (1.13.1), without any data packs, just like it says above. Maybe you're still on 1.13?

violine1101 2019-05-31T11:47:34Z

This issue seems to be back in 1.14+: MC-148613

David Willson 2019-06-15T06:40:20Z

This issue seems to have come back in the latest version. Currently in a 1.14.2 world, I made an aquarium with ~50 bucketed fish, if anyone keeps the aquarium chunks loaded no squid, dolphins, or any other aquatic mob will spawn in anywhere else.

violine1101 2019-06-19T11:00:52Z

→ MC-148613