Ok currently I'm using DTACT to get my values and as everyone must know it has 2 particular memlocs: $info_fish_ID1 and $info_fish_ID2
Basically I'm trying to compile a list of as many of these as I can and as I find them I'm going to be updating this when I can, if you feel like helping or don't mind adding in a few more lines to you scripts to assist me feel free ^.^
I have found that there is duplicates of ID1's or ID2's within their catagory but I have yet to find one with both values the same so currently I am identifying fish, items etc. by the two values. Some of these are incomplete but I do list them as monster fish or item where possible.
I base wether its a monster or fish/item off the "!!!" message recieved.
The reason some are incomplete is because I'm not in the habit of fishing up monsters (plus its not really desired to get a certain monster that I know of) and I've been collecting these while running my scripts which cancells out ones that are undesired (not a certain ID1 & ID2) which is kind of stupid when I think about it seeing as I'm trying to collect the info >.<"

E.Ronfaure: Cheval River
$info_fish_ID1 | $info_fish_ID2 | Fish Name and Type | Rod
----------------------------------------------------------------------------------------
160 | 21 | Fish: Cheval salmon | Carbon
300 | 16 | Monster: Mud Pugil | Carbon
240 | 16 | Fish: Shining Trout | Carbon
60 | 40 | Item: Copper Ring | Carbon
60 | 18 | Monster: Unknown | Carbon

Mahura-Selbina: Ferry
$info_fish_ID1 | $info_fish_ID2 | Fish Name and Type | Rod
----------------------------------------------------------------------------------------
100 | 39 | Fish: Nebimonite | Carbon/Mithran
300 | 20 | Monster: Unknown | Mithran
260 | 20 | Monster: Unknown | Mithran
300 | 19 | Monster: Unknown | Mithran
200 | 39 | Fish or Item | Mithran

Thats all I have so far feel free to post any data that you may have and I'll update this list to save ppl scrolling through the posts.

P.S. Anyone know the syntax for tab spaces here, they don't seem to allow mass " "'s T.T

I have noticed that the fish ID for the same fish is different when using different rod, so you will need to mention which rod you are using

Yes, the values change by rod. Usually a value of 300 for the FishID1 indicates a monster but not always; for example gold carp and ryugu titan is also 300 for FishID1.
Ryugu is 300, 104 for Lu Shang and 300,100 for Hume rod. 60 is usually an item but there is some fish with that FishID1 as well.

MY personal fishbot uses/records into a record

fishname
fishHPlow
fishHPhigh
fishID1
fishID2
zone
rod

the last 4 of those determine a unique(for all intents and purposes) catch result
ie fishID1&fishID2 change based on rod and zone

I only fish certain catches so my record is incomplete but if someone I trust not to redistribute my version wants to use it to generate a comprehensive list then I would be willing to send it to them and help them set it up if they had any problems.

Very interesting, maybe the reason it changes with rods holds something about wether the rod could/will break? Just a theory but it's worth a go, btw some of my results are the same with a Carbon Fish. Rod and a Mithran Fish. Rod, and comparing the results to some other data it is on fish that won't break the rod so who knows...
Alright I'm edditing it to add rods I'm changing the table layout too when I find my other data.

if you want accurate representation for ID's I'd include zone as well and just have a constant that you set for what rod your using. This will generate a cds or xml record cataloging every combination of all the relevant information in one spot.

One thing I noticed about using fish ID is that although the fish ID is the same, the fish itself can be quite different.

For instance, moats in sd w/ halcyon are 200 but (sorry, I forget where) bastore bream are 200 as well.

thats only for 1 of the two fish ID's. There is fishID1 and fishID2 both of which are a integer number. What specific fish a combination of those two will represent changes based on where you are fishing(zone) and what rod you are using. Alot of the time they are the same but more often(from my experience) they are different.

If you do not take all 4 variable into consideration then you cannot garuntee 100% that you KNOW what is on your line and hence whether to drop it or fish it up. Another semirelated thing I noticed with yellow globes and sabiki rig is that the ID's for 1 or 2 fish caught at once were the same but the code for 3 fish at once was different. All this meant was watching both ID combinations though.

Here's a little snippet out of my profile file while i am fishing with my fishing assistant:

<ROW rodname="Lu Shangs fishing rod" zonename="Port Windurst" fishname="3 Bastore sardine" fishid1="160" fishid2="23" wanted="true"/>
<ROW rodname="Hume fishing rod" zonename="Port Windurst" fishname="3 Bastore sardine" fishid1="160" fishid2="26" wanted="true"/>

I've never seen the fish id1 and 2 change based on zone, only on rod.

Yeah I have been doing testing in different zones too, only been to like 2-3 so far but they are the same for me so far.

Fishing on ferry they change from what I remember. Had to fix an issue with it awhile back on mine.

260 | 20 | Monster: Unknown | Mithran
200 | 39 | Fish or Item | Mithran

Both are fish. If I was home I could probably get the type for you, but I'm not home and I'm lazy & forgetful so good luck on when I get home.

not sure what those ID's were for but if you were refering to not getting a good catch name read on some ID's I can explain what I have seen cause that with fish.

Namely when I caught more then one fish at once with a rig it would read as unknown. If I caught the same type of fish with the same rig but only got a single one it read the name fine. I assume this issue is because it is starting the name with a number instead of a letter.

Yeah I've also noted that you can obtain different IDs when using a rig, seems that they have a collective ID for groups of fish caught.

not exactly, I do not know for sure what determines which ID is used but at least with yellow globes I got one ID for both single and double catchs but got a different ID when I caught the triples.