Force ponies to use the seapony model (if they have one) when they are a seapony in unicopia

src/main/java/com/minelittlepony/unicopia/UnicopiaMixinPlugin.java

@@ -35,6 +35,9 @@ public class UnicopiaMixinPlugin implements IMixinConfigPlugin {
             if (mixinClassName.indexOf("ad_astra") != -1) {
                 return FabricLoader.getInstance().isModLoaded("ad_astra");
             }
+            if (mixinClassName.indexOf("minelp") != -1) {
+                return FabricLoader.getInstance().isModLoaded("minelp");
+            }
         }
         return true;
     }

src/main/java/com/minelittlepony/unicopia/mixin/client/minelp/MixinPonyPosture.java

@@ -0,0 +1,22 @@
+package com.minelittlepony.unicopia.mixin.client.minelp;
+
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+import com.minelittlepony.api.pony.PonyPosture;
+import com.minelittlepony.unicopia.Race;
+import com.minelittlepony.unicopia.entity.player.Pony;
+
+import net.minecraft.entity.LivingEntity;
+
+@Mixin(PonyPosture.class)
+abstract class MixinPonyPosture {
+    @Inject(method = "isPartiallySubmerged", at = @At("HEAD"), cancellable = true)
+    private static void isPartiallySubmerged(LivingEntity entity, CallbackInfoReturnable<Boolean> info) {
+        if (Pony.of(entity).filter(pony -> pony.getCompositeRace().includes(Race.SEAPONY)).isPresent()) {
+            info.setReturnValue(true);
+        }
+    }
+}

src/main/resources/unicopia.mixin.json

@@ -78,6 +78,7 @@
     "client.MixinTranslationStorage",
     "client.MixinWorldRenderer",
     "client.sodium.MixinSodiumWorldRenderer",
+    "client.minelp.MixinPonyPosture",
     "trinkets.MixinTrinketCreativeSlot"
   ],
   "injectors": {